path: root/src/glamor_gradient.c

/*
 * Copyright © 2009 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Junyan He <junyan.he@linux.intel.com>
 *
 */

/** @file glamor_gradient.c
 *
 * Gradient acceleration implementation
 */

#include "glamor_priv.h"

#ifdef RENDER

#define LINEAR_SMALL_STOPS (6 + 2)
#define LINEAR_LARGE_STOPS (16 + 2)

#define RADIAL_SMALL_STOPS (6 + 2)
#define RADIAL_LARGE_STOPS (16 + 2)

#ifdef GLAMOR_GRADIENT_SHADER

static GLint
_glamor_create_getcolor_fs_program(ScreenPtr screen, int stops_count, int use_array)
{
	glamor_screen_private *glamor_priv;
	glamor_gl_dispatch *dispatch;

	char *gradient_fs = NULL;
	GLint fs_getcolor_prog;

	#define gradient_fs_getcolor\
	    GLAMOR_DEFAULT_PRECISION\
	    "uniform int n_stop;\n"\
	    "uniform float stops[%d];\n"\
	    "uniform vec4 stop_colors[%d];\n"\
	    "vec4 get_color(float stop_len)\n"\
	    "{\n"\
	    "    int i = 0;\n"\
	    "    float new_alpha; \n"\
	    "    vec4 gradient_color;\n"\
	    "    float percentage; \n"\
	    "    for(i = 0; i < n_stop - 1; i++) {\n"\
	    "        if(stop_len < stops[i])\n"\
	    "            break; \n"\
	    "    }\n"\
	    "    \n"\
	    "    if(stops[i] - stops[i-1] > 2.0)\n"\
	    "        percentage = 0.0;\n" /*For comply with pixman, walker->stepper overflow.*/\
	    "    else if(stops[i] - stops[i-1] < 0.000001)\n"\
	    "        percentage = 0.0;\n"\
	    "    else \n"\
	    "        percentage = (stop_len - stops[i-1])/(stops[i] - stops[i-1]);\n"\
	    "    new_alpha = percentage * stop_colors[i].a + \n"\
	    "                       (1.0-percentage) * stop_colors[i-1].a; \n"\
	    "    gradient_color = vec4((percentage * stop_colors[i].rgb \n"\
	    "                          + (1.0-percentage) * stop_colors[i-1].rgb)*new_alpha, \n"\
	    "                          new_alpha);\n"\
	    "    \n"\
	    "    return gradient_color;\n"\
	    "}\n"

	/* Because the array access for shader is very slow, the performance is very low
	   if use array. So use global uniform to replace for it if the number of n_stops is small.*/
	const char *gradient_fs_getcolor_no_array =
	    GLAMOR_DEFAULT_PRECISION
	    "uniform int n_stop;\n"
	    "uniform float stop0;\n"
	    "uniform float stop1;\n"
	    "uniform float stop2;\n"
	    "uniform float stop3;\n"
	    "uniform float stop4;\n"
	    "uniform float stop5;\n"
	    "uniform float stop6;\n"
	    "uniform float stop7;\n"
	    "uniform vec4 stop_color0;\n"
	    "uniform vec4 stop_color1;\n"
	    "uniform vec4 stop_color2;\n"
	    "uniform vec4 stop_color3;\n"
	    "uniform vec4 stop_color4;\n"
	    "uniform vec4 stop_color5;\n"
	    "uniform vec4 stop_color6;\n"
	    "uniform vec4 stop_color7;\n"
	    "\n"
	    "vec4 get_color(float stop_len)\n"
	    "{\n"
	    "    float stop_after;\n"
	    "    float stop_before;\n"
	    "    vec4 stop_color_before;\n"
	    "    vec4 stop_color_after;\n"
	    "    float new_alpha; \n"
	    "    vec4 gradient_color;\n"
	    "    float percentage; \n"
	    "    \n"
	    "    if((stop_len < stop0) && (n_stop >= 1)) {\n"
	    "        stop_color_before = stop_color0;\n"
	    "        stop_color_after = stop_color0;\n"
	    "        stop_after = stop0;\n"
	    "        stop_before = stop0;\n"
	    "    } else if((stop_len < stop1) && (n_stop >= 2)) {\n"
	    "        stop_color_before = stop_color0;\n"
	    "        stop_color_after = stop_color1;\n"
	    "        stop_after = stop1;\n"
	    "        stop_before = stop0;\n"
	    "    } else if((stop_len < stop2) && (n_stop >= 3)) {\n"
	    "        stop_color_before = stop_color1;\n"
	    "        stop_color_after = stop_color2;\n"
	    "        stop_after = stop2;\n"
	    "        stop_before = stop1;\n"
	    "    } else if((stop_len < stop3) && (n_stop >= 4)){\n"
	    "        stop_color_before = stop_color2;\n"
	    "        stop_color_after = stop_color3;\n"
	    "        stop_after = stop3;\n"
	    "        stop_before = stop2;\n"
	    "    } else if((stop_len < stop4) && (n_stop >= 5)){\n"
	    "        stop_color_before = stop_color3;\n"
	    "        stop_color_after = stop_color4;\n"
	    "        stop_after = stop4;\n"
	    "        stop_before = stop3;\n"
	    "    } else if((stop_len < stop5) && (n_stop >= 6)){\n"
	    "        stop_color_before = stop_color4;\n"
	    "        stop_color_after = stop_color5;\n"
	    "        stop_after = stop5;\n"
	    "        stop_before = stop4;\n"
	    "    } else if((stop_len < stop6) && (n_stop >= 7)){\n"
	    "        stop_color_before = stop_color5;\n"
	    "        stop_color_after = stop_color6;\n"
	    "        stop_after = stop6;\n"
	    "        stop_before = stop5;\n"
	    "    } else if((stop_len < stop7) && (n_stop >= 8)){\n"
	    "        stop_color_before = stop_color6;\n"
	    "        stop_color_after = stop_color7;\n"
	    "        stop_after = stop7;\n"
	    "        stop_before = stop6;\n"
	    "    } else {\n"
	    "        stop_color_before = stop_color7;\n"
	    "        stop_color_after = stop_color7;\n"
	    "        stop_after = stop7;\n"
	    "        stop_before = stop7;\n"
	    "    }\n"
	    "    if(stop_after - stop_before > 2.0)\n"
	    "        percentage = 0.0;\n"//For comply with pixman, walker->stepper overflow.
	    "    else if(stop_after - stop_before < 0.000001)\n"
	    "        percentage = 0.0;\n"
	    "    else \n"
	    "        percentage = (stop_len - stop_before)/(stop_after - stop_before);\n"
	    "    new_alpha = percentage * stop_color_after.a + \n"
	    "                       (1.0-percentage) * stop_color_before.a; \n"
	    "    gradient_color = vec4((percentage * stop_color_after.rgb \n"
	    "                          + (1.0-percentage) * stop_color_before.rgb)*new_alpha, \n"
	    "                          new_alpha);\n"
	    "    \n"
	    "    return gradient_color;\n"
	    "}\n";

	glamor_priv = glamor_get_screen_private(screen);
	dispatch = glamor_get_dispatch(glamor_priv);

	if(use_array) {
		XNFasprintf(&gradient_fs,
		    gradient_fs_getcolor, stops_count, stops_count);
		fs_getcolor_prog = glamor_compile_glsl_prog(dispatch, GL_FRAGMENT_SHADER,
		                                            gradient_fs);
		free(gradient_fs);
	} else {
		fs_getcolor_prog = glamor_compile_glsl_prog(dispatch, GL_FRAGMENT_SHADER,
		                                            gradient_fs_getcolor_no_array);
	}

	return fs_getcolor_prog;
}

static void
_glamor_create_radial_gradient_program(ScreenPtr screen, int stops_count, int dyn_gen)
{
	glamor_screen_private *glamor_priv;
	glamor_gl_dispatch *dispatch;
	int index;

	GLint gradient_prog = 0;
	char *gradient_fs = NULL;
	GLint fs_main_prog, fs_getcolor_prog, vs_prog;

	const char *gradient_vs =
	    GLAMOR_DEFAULT_PRECISION
	    "attribute vec4 v_position;\n"
	    "attribute vec4 v_texcoord;\n"
	    "varying vec2 source_texture;\n"
	    "\n"
	    "void main()\n"
	    "{\n"
	    "    gl_Position = v_position;\n"
	    "    source_texture = v_texcoord.xy;\n"
	    "}\n";

	/*
	 *     Refer to pixman radial gradient.
	 *
	 *     The problem is given the two circles of c1 and c2 with the radius of r1 and
	 *     r1, we need to caculate the t, which is used to do interpolate with stops,
	 *     using the fomula:
	 *     length((1-t)*c1 + t*c2 - p) = (1-t)*r1 + t*r2
	 *     expand the fomula with xy coond, get the following:
	 *     sqrt(sqr((1-t)*c1.x + t*c2.x - p.x) + sqr((1-t)*c1.y + t*c2.y - p.y))
	 *           = (1-t)r1 + t*r2
	 *     <====> At*t- 2Bt + C = 0
	 *     where A = sqr(c2.x - c1.x) + sqr(c2.y - c1.y) - sqr(r2 -r1)
	 *           B = (p.x - c1.x)*(c2.x - c1.x) + (p.y - c1.y)*(c2.y - c1.y) + r1*(r2 -r1)
	 *           C = sqr(p.x - c1.x) + sqr(p.y - c1.y) - r1*r1
	 *
	 *     solve the fomula and we get the result of
	 *     t = (B + sqrt(B*B - A*C)) / A  or
	 *     t = (B - sqrt(B*B - A*C)) / A  (quadratic equation have two solutions)
	 *
	 *     The solution we are going to prefer is the bigger one, unless the
	 *     radius associated to it is negative (or it falls outside the valid t range)
	 */

	#define gradient_radial_fs_template\
	    GLAMOR_DEFAULT_PRECISION\
	    "uniform mat3 transform_mat;\n"\
	    "uniform int repeat_type;\n"\
	    "uniform float A_value;\n"\
	    "uniform vec2 c1;\n"\
	    "uniform float r1;\n"\
	    "uniform vec2 c2;\n"\
	    "uniform float r2;\n"\
	    "varying vec2 source_texture;\n"\
	    "\n"\
	    "vec4 get_color(float stop_len);\n"\
	    "\n"\
	    "int t_invalid;\n"\
	    "\n"\
	    "float get_stop_len()\n"\
	    "{\n"\
	    "    float t = 0.0;\n"\
	    "    float sqrt_value;\n"\
	    "    t_invalid = 0;\n"\
	    "    \n"\
	    "    vec3 tmp = vec3(source_texture.x, source_texture.y, 1.0);\n"\
	    "    vec3 source_texture_trans = transform_mat * tmp;\n"\
	    "    source_texture_trans.xy = source_texture_trans.xy/source_texture_trans.z;\n"\
	    "    float B_value = (source_texture_trans.x - c1.x) * (c2.x - c1.x)\n"\
	    "                     + (source_texture_trans.y - c1.y) * (c2.y - c1.y)\n"\
	    "                     + r1 * (r2 - r1);\n"\
	    "    float C_value = (source_texture_trans.x - c1.x) * (source_texture_trans.x - c1.x)\n"\
	    "                     + (source_texture_trans.y - c1.y) * (source_texture_trans.y - c1.y)\n"\
	    "                     - r1*r1;\n"\
	    "    if(abs(A_value) < 0.00001) {\n"\
	    "        if(B_value == 0.0) {\n"\
	    "            t_invalid = 1;\n"\
	    "            return t;\n"\
	    "        }\n"\
	    "        t = 0.5 * C_value / B_value;"\
	    "    } else {\n"\
	    "        sqrt_value = B_value * B_value - A_value * C_value;\n"\
	    "        if(sqrt_value < 0.0) {\n"\
	    "            t_invalid = 1;\n"\
	    "            return t;\n"\
	    "        }\n"\
	    "        sqrt_value = sqrt(sqrt_value);\n"\
	    "        t = (B_value + sqrt_value) / A_value;\n"\
	    "    }\n"\
	    "    if(repeat_type == %d) {\n" /* RepeatNone case. */\
	    "        if((t <= 0.0) || (t > 1.0))\n"\
	    /*           try another if first one invalid*/\
	    "            t = (B_value - sqrt_value) / A_value;\n"\
	    "        \n"\
	    "        if((t <= 0.0) || (t > 1.0)) {\n" /*still invalid, return.*/\
	    "            t_invalid = 1;\n"\
	    "            return t;\n"\
	    "        }\n"\
	    "    } else {\n"\
	    "        if(t * (r2 - r1) <= -1.0 * r1)\n"\
	    /*           try another if first one invalid*/\
	    "            t = (B_value - sqrt_value) / A_value;\n"\
	    "        \n"\
	    "        if(t * (r2 -r1) <= -1.0 * r1) {\n" /*still invalid, return.*/\
	    "            t_invalid = 1;\n"\
	    "            return t;\n"\
	    "        }\n"\
	    "    }\n"\
	    "    \n"\
	    "    if(repeat_type == %d){\n" /* repeat normal*/\
	    "        t = fract(t);\n"\
	    "    }\n"\
	    "    \n"\
	    "    if(repeat_type == %d) {\n" /* repeat reflect*/\
	    "        t = abs(fract(t * 0.5 + 0.5) * 2.0 - 1.0);\n"\
	    "    }\n"\
	    "    \n"\
	    "    return t;\n"\
	    "}\n"\
	    "\n"\
	    "void main()\n"\
	    "{\n"\
	    "    float stop_len = get_stop_len();\n"\
	    "    if(t_invalid == 1) {\n"\
	    "        gl_FragColor = vec4(0.0, 0.0, 0.0, 0.0);\n"\
	    "    } else {\n"\
	    "        gl_FragColor = get_color(stop_len);\n"\
	    "    }\n"\
	    "}\n"

	glamor_priv = glamor_get_screen_private(screen);

	if ((glamor_priv->radial_max_nstops >= stops_count) && (dyn_gen)) {
		/* Very Good, not to generate again. */
		return;
	}

	dispatch = glamor_get_dispatch(glamor_priv);

	if (dyn_gen && glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][2]) {
		dispatch->glDeleteProgram(glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][2]);
		glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][2] = 0;
	}

	gradient_prog = dispatch->glCreateProgram();

	vs_prog = glamor_compile_glsl_prog(dispatch,
	                                   GL_VERTEX_SHADER, gradient_vs);

	XNFasprintf(&gradient_fs,
	            gradient_radial_fs_template,
	            PIXMAN_REPEAT_NONE, PIXMAN_REPEAT_NORMAL, PIXMAN_REPEAT_REFLECT);

	fs_main_prog = glamor_compile_glsl_prog(dispatch,
	                                        GL_FRAGMENT_SHADER, gradient_fs);

	free(gradient_fs);

	fs_getcolor_prog =
	    _glamor_create_getcolor_fs_program(screen, stops_count, (stops_count > 0));

	dispatch->glAttachShader(gradient_prog, vs_prog);
	dispatch->glAttachShader(gradient_prog, fs_getcolor_prog);
	dispatch->glAttachShader(gradient_prog, fs_main_prog);
	dispatch->glDeleteShader(vs_prog);
	dispatch->glDeleteShader(fs_getcolor_prog);
	dispatch->glDeleteShader(fs_main_prog);

	dispatch->glBindAttribLocation(gradient_prog, GLAMOR_VERTEX_POS, "v_position");
	dispatch->glBindAttribLocation(gradient_prog, GLAMOR_VERTEX_SOURCE, "v_texcoord");

	glamor_link_glsl_prog(dispatch, gradient_prog);

	dispatch->glUseProgram(0);

	if (dyn_gen) {
		index = 2;
		glamor_priv->radial_max_nstops = stops_count;
	} else if (stops_count) {
		index = 1;
	} else {
		index = 0;
	}

	glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][index] = gradient_prog;

	glamor_put_dispatch(glamor_priv);
}

static void
_glamor_create_linear_gradient_program(ScreenPtr screen, int stops_count, int dyn_gen)
{
	glamor_screen_private *glamor_priv;
	glamor_gl_dispatch *dispatch;

	int index = 0;
	GLint gradient_prog = 0;
	char *gradient_fs = NULL;
	GLint fs_main_prog, fs_getcolor_prog, vs_prog;

	const char *gradient_vs =
	    GLAMOR_DEFAULT_PRECISION
	    "attribute vec4 v_position;\n"
	    "attribute vec4 v_texcoord;\n"
	    "varying vec2 source_texture;\n"
	    "\n"
	    "void main()\n"
	    "{\n"
	    "    gl_Position = v_position;\n"
	    "    source_texture = v_texcoord.xy;\n"
	    "}\n";

	/*
	 *                                      |
	 *                                      |\
	 *                                      | \
	 *                                      |  \
	 *                                      |   \
	 *                                      |\   \
	 *                                      | \   \
	 *     cos_val =                        |\ p1d \   /
	 *      sqrt(1/(slope*slope+1.0))  ------>\ \   \ /
	 *                                      |  \ \   \
	 *                                      |   \ \ / \
	 *                                      |    \ *Pt1\
	 *         *p1                          |     \     \     *P
	 *          \                           |    / \     \   /
	 *           \                          |   /   \     \ /
	 *            \                         |       pd     \
	 *             \                        |         \   / \
	 *            p2*                       |          \ /   \       /
	 *        slope = (p2.y - p1.y) /       |           /     p2d   /
	 *                    (p2.x - p1.x)     |          /       \   /
	 *                                      |         /         \ /
	 *                                      |        /           /
	 *                                      |       /           /
	 *                                      |      /           *Pt2
	 *                                      |                 /
	 *                                      |                /
	 *                                      |               /
	 *                                      |              /
	 *                                      |             /
	 *                               -------+---------------------------------
	 *                                     O|
	 *                                      |
	 *                                      |
	 *
	 *	step 1: compute the distance of p, pt1 and pt2 in the slope direction.
	 *		Caculate the distance on Y axis first and multiply cos_val to
	 *		get the value on slope direction(pd, p1d and p2d represent the
	 *		distance of p, pt1, and pt2 respectively).
	 *
	 *	step 2: caculate the percentage of (pd - p1d)/(p2d - p1d).
	 *		If (pd - p1d) > (p2d - p1d) or < 0, then sub or add (p2d - p1d)
	 *		to make it in the range of [0, (p2d - p1d)].
	 *
	 *	step 3: compare the percentage to every stop and find the stpos just
	 *		before and after it. Use the interpolation fomula to compute RGBA.
	 */

	#define gradient_fs_template	\
	    GLAMOR_DEFAULT_PRECISION\
	    "uniform mat3 transform_mat;\n"\
	    "uniform int repeat_type;\n"\
	    "uniform int hor_ver;\n"\
	    "uniform float pt_slope;\n"\
	    "uniform float cos_val;\n"\
	    "uniform float p1_distance;\n"\
	    "uniform float pt_distance;\n"\
	    "varying vec2 source_texture;\n"\
	    "\n"\
	    "vec4 get_color(float stop_len);\n"\
	    "\n"\
	    "float get_stop_len()\n"\
	    "{\n"\
	    "    vec3 tmp = vec3(source_texture.x, source_texture.y, 1.0);\n"\
	    "    float len_percentage;\n"\
	    "    float distance;\n"\
	    "    float _p1_distance;\n"\
	    "    float _pt_distance;\n"\
	    "    float y_dist;\n"\
	    "    float stop_after;\n"\
	    "    float stop_before;\n"\
	    "    vec4 stop_color_before;\n"\
	    "    vec4 stop_color_after;\n"\
	    "    float new_alpha; \n"\
	    "    vec4 gradient_color;\n"\
	    "    float percentage; \n"\
	    "    vec3 source_texture_trans = transform_mat * tmp;\n"\
	    "    \n"\
	    "    if(hor_ver == 0) { \n" /*Normal case.*/\
	    "        y_dist = source_texture_trans.y - source_texture_trans.x*pt_slope;\n"\
	    "        distance = y_dist * cos_val;\n"\
	    "        _p1_distance = p1_distance * source_texture_trans.z;\n"\
	    "        _pt_distance = pt_distance * source_texture_trans.z;\n"\
	    "        \n"\
	    "    } else if (hor_ver == 1) {\n"/*horizontal case.*/\
	    "        distance = source_texture_trans.x;\n"\
	    "        _p1_distance = p1_distance * source_texture_trans.z;\n"\
	    "        _pt_distance = pt_distance * source_texture_trans.z;\n"\
	    "    } \n"\
	    "    \n"\
	    "    distance = distance - _p1_distance; \n"\
	    "    \n"\
	    "    if(repeat_type == %d){\n" /* repeat normal*/\
	    "        distance = mod(distance, _pt_distance);\n"\
	    "    }\n"\
	    "    \n"\
	    "    if(repeat_type == %d) {\n" /* repeat reflect*/\
	    "        distance = abs(mod(distance + _pt_distance, 2.0 * _pt_distance) - _pt_distance);\n"\
	    "    }\n"\
	    "    \n"\
	    "    len_percentage = distance/(_pt_distance);\n"\
	    "    \n"\
	    "    return len_percentage;\n"\
	    "}\n"\
	    "\n"\
	    "void main()\n"\
	    "{\n"\
	    "    float stop_len = get_stop_len();\n"\
	    "    gl_FragColor = get_color(stop_len);\n"\
	    "}\n"

	glamor_priv = glamor_get_screen_private(screen);

	if ((glamor_priv->linear_max_nstops >= stops_count) && (dyn_gen)) {
		/* Very Good, not to generate again. */
		return;
	}

	dispatch = glamor_get_dispatch(glamor_priv);
	if (dyn_gen && glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][2]) {
		dispatch->glDeleteProgram(glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][2]);
		glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][2] = 0;
	}

	gradient_prog = dispatch->glCreateProgram();

	vs_prog = glamor_compile_glsl_prog(dispatch,
	                                   GL_VERTEX_SHADER, gradient_vs);

	XNFasprintf(&gradient_fs,
	            gradient_fs_template,
	            PIXMAN_REPEAT_NORMAL, PIXMAN_REPEAT_REFLECT);

	fs_main_prog = glamor_compile_glsl_prog(dispatch,
	                                        GL_FRAGMENT_SHADER, gradient_fs);
	free(gradient_fs);

	fs_getcolor_prog =
	    _glamor_create_getcolor_fs_program(screen, stops_count, (stops_count > 0));

	dispatch->glAttachShader(gradient_prog, vs_prog);
	dispatch->glAttachShader(gradient_prog, fs_getcolor_prog);
	dispatch->glAttachShader(gradient_prog, fs_main_prog);
	dispatch->glDeleteShader(vs_prog);
	dispatch->glDeleteShader(fs_getcolor_prog);
	dispatch->glDeleteShader(fs_main_prog);

	dispatch->glBindAttribLocation(gradient_prog, GLAMOR_VERTEX_POS, "v_position");
	dispatch->glBindAttribLocation(gradient_prog, GLAMOR_VERTEX_SOURCE, "v_texcoord");

	glamor_link_glsl_prog(dispatch, gradient_prog);

	dispatch->glUseProgram(0);

	if (dyn_gen) {
		index = 2;
		glamor_priv->linear_max_nstops = stops_count;
	} else if (stops_count) {
		index = 1;
	} else {
		index = 0;
	}

	glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][index] = gradient_prog;

	glamor_put_dispatch(glamor_priv);
}

void
glamor_init_gradient_shader(ScreenPtr screen)
{
	glamor_screen_private *glamor_priv;
	int i;

	glamor_priv = glamor_get_screen_private(screen);

	for (i = 0; i < 3; i++) {
		glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][i] = 0;

		glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][i] = 0;
	}
	glamor_priv->linear_max_nstops = 0;
	glamor_priv->radial_max_nstops = 0;

	_glamor_create_linear_gradient_program(screen, 0, 0);
	_glamor_create_linear_gradient_program(screen, LINEAR_LARGE_STOPS, 0);

	_glamor_create_radial_gradient_program(screen, 0, 0);
	_glamor_create_radial_gradient_program(screen, RADIAL_LARGE_STOPS, 0);
}

void
glamor_fini_gradient_shader(ScreenPtr screen)
{
	glamor_screen_private *glamor_priv;
	glamor_gl_dispatch *dispatch;
	int i = 0;

	glamor_priv = glamor_get_screen_private(screen);
	dispatch = glamor_get_dispatch(glamor_priv);

	for (i = 0; i < 3; i++) {
		/* Linear Gradient */
		if (glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][i])
			dispatch->glDeleteProgram(glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][i]);

		/* Radial Gradient */
		if (glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][i])
			dispatch->glDeleteProgram(glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][i]);
	}

	glamor_put_dispatch(glamor_priv);
}

static void
_glamor_gradient_convert_trans_matrix(PictTransform *from, float to[3][3],
				      int width, int height, int normalize)
{
	/*
	 * Because in the shader program, we normalize all the pixel cood to [0, 1],
	 * so with the transform matrix, the correct logic should be:
	 * v_s = A*T*v
	 * v_s: point vector in shader after normalized.
	 * A: The transition matrix from   width X height --> 1.0 X 1.0
	 * T: The transform matrix.
	 * v: point vector in width X height space.
	 *
	 * result is OK if we use this fomula. But for every point in width X height space,
	 * we can just use their normalized point vector in shader, namely we can just
	 * use the result of A*v in shader. So we have no chance to insert T in A*v.
	 * We can just convert v_s = A*T*v to v_s = A*T*inv(A)*A*v, where inv(A) is the
	 * inverse matrix of A. Now, v_s = (A*T*inv(A)) * (A*v)
	 * So, to get the correct v_s, we need to cacula1 the matrix: (A*T*inv(A)), and
	 * we name this matrix T_s.
	 *
	 * Firstly, because A is for the scale convertion, we find
	 *      --         --
	 *      |1/w  0   0 |
	 * A =  | 0  1/h  0 |
	 *      | 0   0  1.0|
	 *      --         --
	 * so T_s = A*T*inv(a) and result
	 *
	 *       --                      --
	 *       | t11      h*t12/w  t13/w|
	 * T_s = | w*t21/h  t22      t23/h|
	 *       | w*t31    h*t32    t33  |
	 *       --                      --
	 */

	to[0][0] = (float)pixman_fixed_to_double(from->matrix[0][0]);
	to[0][1] = (float)pixman_fixed_to_double(from->matrix[0][1])
	                        * (normalize ? (((float)height) / ((float)width)) : 1.0);
	to[0][2] = (float)pixman_fixed_to_double(from->matrix[0][2])
	                        / (normalize ? ((float)width) : 1.0);

	to[1][0] = (float)pixman_fixed_to_double(from->matrix[1][0])
	                        * (normalize ? (((float)width) / ((float)height)) : 1.0);
	to[1][1] = (float)pixman_fixed_to_double(from->matrix[1][1]);
	to[1][2] = (float)pixman_fixed_to_double(from->matrix[1][2])
	                        / (normalize ? ((float)height) : 1.0);

	to[2][0] = (float)pixman_fixed_to_double(from->matrix[2][0])
	                        * (normalize ? ((float)width) : 1.0);
	to[2][1] = (float)pixman_fixed_to_double(from->matrix[2][1])
	                        * (normalize ? ((float)height) : 1.0);
	to[2][2] = (float)pixman_fixed_to_double(from->matrix[2][2]);

	DEBUGF("the transform matrix is:\n%f\t%f\t%f\n%f\t%f\t%f\n%f\t%f\t%f\n",
	       to[0][0], to[0][1], to[0][2],
	       to[1][0], to[1][1], to[1][2],
	       to[2][0], to[2][1], to[2][2]);
}

static int
_glamor_gradient_set_pixmap_destination(ScreenPtr screen,
                                        glamor_screen_private *glamor_priv,
                                        PicturePtr dst_picture,
                                        GLfloat *xscale, GLfloat *yscale,
                                        int x_source, int y_source,
                                        float vertices[8],
                                        float tex_vertices[8],
					int tex_normalize)
{
	glamor_pixmap_private *pixmap_priv;
	PixmapPtr pixmap = NULL;
	glamor_gl_dispatch *dispatch = NULL;

	pixmap = glamor_get_drawable_pixmap(dst_picture->pDrawable);
	pixmap_priv = glamor_get_pixmap_private(pixmap);

	if (!GLAMOR_PIXMAP_PRIV_HAS_FBO(pixmap_priv)) { /* should always have here. */
		return 0;
	}

	glamor_set_destination_pixmap_priv_nc(pixmap_priv);

	pixmap_priv_get_dest_scale(pixmap_priv, xscale, yscale);

	DEBUGF("xscale = %f, yscale = %f,"
	       " x_source = %d, y_source = %d, width = %d, height = %d\n",
	       *xscale, *yscale, x_source, y_source,
	       dst_picture->pDrawable->width, dst_picture->pDrawable->height);

	glamor_set_normalize_vcoords_tri_strip(*xscale, *yscale,
	                  0, 0,
	                  (INT16)(dst_picture->pDrawable->width),
	                  (INT16)(dst_picture->pDrawable->height),
	                  glamor_priv->yInverted, vertices);

	if (tex_normalize) {
		glamor_set_normalize_tcoords_tri_stripe(*xscale, *yscale,
		                x_source, y_source,
		                (INT16)(dst_picture->pDrawable->width + x_source),
		                (INT16)(dst_picture->pDrawable->height + y_source),
		                glamor_priv->yInverted, tex_vertices);
	} else {
		glamor_set_tcoords_tri_strip((INT16)(dst_picture->pDrawable->width),
		                 (INT16)(dst_picture->pDrawable->height),
		                 x_source, y_source,
		                 (INT16)(dst_picture->pDrawable->width) + x_source,
		                 (INT16)(dst_picture->pDrawable->height) + y_source,
		                 glamor_priv->yInverted, tex_vertices);
	}

	DEBUGF("vertices --> leftup : %f X %f, rightup: %f X %f,"
	       "rightbottom: %f X %f, leftbottom : %f X %f\n",
	       vertices[0], vertices[1], vertices[2], vertices[3],
	       vertices[4], vertices[5], vertices[6], vertices[7]);
	DEBUGF("tex_vertices --> leftup : %f X %f, rightup: %f X %f,"
	       "rightbottom: %f X %f, leftbottom : %f X %f\n",
	       tex_vertices[0], tex_vertices[1], tex_vertices[2], tex_vertices[3],
	       tex_vertices[4], tex_vertices[5], tex_vertices[6], tex_vertices[7]);

	dispatch = glamor_get_dispatch(glamor_priv);

	dispatch->glVertexAttribPointer(GLAMOR_VERTEX_POS, 2, GL_FLOAT,
					GL_FALSE, 0, vertices);
	dispatch->glVertexAttribPointer(GLAMOR_VERTEX_SOURCE, 2, GL_FLOAT,
					GL_FALSE, 0, tex_vertices);

	dispatch->glEnableVertexAttribArray(GLAMOR_VERTEX_POS);
	dispatch->glEnableVertexAttribArray(GLAMOR_VERTEX_SOURCE);

	glamor_put_dispatch(glamor_priv);

	return 1;
}

static int
_glamor_gradient_set_stops(PicturePtr src_picture, PictGradient * pgradient,
        GLfloat *stop_colors, GLfloat *n_stops)
{
	int i;
	int count = 1;

	for (i = 0; i < pgradient->nstops; i++) {
		stop_colors[count*4] = pixman_fixed_to_double(
		                                pgradient->stops[i].color.red);
		stop_colors[count*4+1] = pixman_fixed_to_double(
		                                pgradient->stops[i].color.green);
		stop_colors[count*4+2] = pixman_fixed_to_double(
		                                pgradient->stops[i].color.blue);
		stop_colors[count*4+3] = pixman_fixed_to_double(
		                                pgradient->stops[i].color.alpha);

		n_stops[count] = (GLfloat)pixman_fixed_to_double(
		                                pgradient->stops[i].x);
		count++;
	}

	/* for the end stop. */
	count++;

	switch (src_picture->repeatType) {
#define REPEAT_FILL_STOPS(m, n) \
			stop_colors[(m)*4 + 0] = stop_colors[(n)*4 + 0]; \
			stop_colors[(m)*4 + 1] = stop_colors[(n)*4 + 1]; \
			stop_colors[(m)*4 + 2] = stop_colors[(n)*4 + 2]; \
			stop_colors[(m)*4 + 3] = stop_colors[(n)*4 + 3];

		default:
		case PIXMAN_REPEAT_NONE:
			stop_colors[0] = 0.0;	   //R
			stop_colors[1] = 0.0;	   //G
			stop_colors[2] = 0.0;	   //B
			stop_colors[3] = 0.0;	   //Alpha
			n_stops[0] = -(float)INT_MAX;  //should be small enough.

			stop_colors[0 + (count-1)*4] = 0.0;	 //R
			stop_colors[1 + (count-1)*4] = 0.0;	 //G
			stop_colors[2 + (count-1)*4] = 0.0;	 //B
			stop_colors[3 + (count-1)*4] = 0.0;	 //Alpha
			n_stops[count-1] = (float)INT_MAX;  //should be large enough.
			break;
		case PIXMAN_REPEAT_NORMAL:
			REPEAT_FILL_STOPS(0, count - 2);
			n_stops[0] = n_stops[count-2] - 1.0;

			REPEAT_FILL_STOPS(count - 1, 1);
			n_stops[count-1] = n_stops[1] + 1.0;
			break;
		case PIXMAN_REPEAT_REFLECT:
			REPEAT_FILL_STOPS(0, 1);
			n_stops[0] = -n_stops[1];

			REPEAT_FILL_STOPS(count - 1, count - 2);
			n_stops[count-1] = 1.0 + 1.0 - n_stops[count-2];
			break;
		case PIXMAN_REPEAT_PAD:
			REPEAT_FILL_STOPS(0, 1);
			n_stops[0] = -(float)INT_MAX;

			REPEAT_FILL_STOPS(count - 1, count - 2);
			n_stops[count-1] = (float)INT_MAX;
			break;
#undef REPEAT_FILL_STOPS
	}

	for (i = 0; i < count; i++) {
		DEBUGF("n_stops[%d] = %f, color = r:%f g:%f b:%f a:%f\n",
		       i, n_stops[i],
		       stop_colors[i*4], stop_colors[i*4+1],
		       stop_colors[i*4+2], stop_colors[i*4+3]);
	}

	return count;
}

PicturePtr
glamor_generate_radial_gradient_picture(ScreenPtr screen,
                                         PicturePtr src_picture,
                                         int x_source, int y_source,
                                         int width, int height,
                                         PictFormatShort format)
{
	glamor_screen_private *glamor_priv;
	glamor_gl_dispatch *dispatch;
	PicturePtr dst_picture = NULL;
	PixmapPtr pixmap = NULL;
	GLint gradient_prog = 0;
	int error;
	float tex_vertices[8];
	int stops_count = 0;
	int count = 0;
	GLfloat *stop_colors = NULL;
	GLfloat *n_stops = NULL;
	GLfloat xscale, yscale;
	float vertices[8];
	float transform_mat[3][3];
	static const float identity_mat[3][3] = {{1.0, 0.0, 0.0},
	                                         {0.0, 1.0, 0.0},
	                                         {0.0, 0.0, 1.0}};
	GLfloat stop_colors_st[RADIAL_SMALL_STOPS*4];
	GLfloat n_stops_st[RADIAL_SMALL_STOPS];
	GLfloat A_value;
	GLfloat cxy[4];
	float c1x, c1y, c2x, c2y, r1, r2;

	GLint transform_mat_uniform_location = 0;
	GLint repeat_type_uniform_location = 0;
	GLint n_stop_uniform_location = 0;
	GLint stops_uniform_location = 0;
	GLint stop_colors_uniform_location = 0;
	GLint stop0_uniform_location = 0;
	GLint stop1_uniform_location = 0;
	GLint stop2_uniform_location = 0;
	GLint stop3_uniform_location = 0;
	GLint stop4_uniform_location = 0;
	GLint stop5_uniform_location = 0;
	GLint stop6_uniform_location = 0;
	GLint stop7_uniform_location = 0;
	GLint stop_color0_uniform_location = 0;
	GLint stop_color1_uniform_location = 0;
	GLint stop_color2_uniform_location = 0;
	GLint stop_color3_uniform_location = 0;
	GLint stop_color4_uniform_location = 0;
	GLint stop_color5_uniform_location = 0;
	GLint stop_color6_uniform_location = 0;
	GLint stop_color7_uniform_location = 0;
	GLint A_value_uniform_location = 0;
	GLint c1_uniform_location = 0;
	GLint r1_uniform_location = 0;
	GLint c2_uniform_location = 0;
	GLint r2_uniform_location = 0;

	glamor_priv = glamor_get_screen_private(screen);
	dispatch = glamor_get_dispatch(glamor_priv);

	/* Create a pixmap with VBO. */
	pixmap = glamor_create_pixmap(screen,
	                              width, height,
	                              PIXMAN_FORMAT_DEPTH(format),
	                              0);
	if (!pixmap)
		goto GRADIENT_FAIL;

	dst_picture = CreatePicture(0, &pixmap->drawable,
	                            PictureMatchFormat(screen,
	                                 PIXMAN_FORMAT_DEPTH(format), format),
	                            0, 0, serverClient, &error);

	/* Release the reference, picture will hold the last one. */
	glamor_destroy_pixmap(pixmap);

	if (!dst_picture)
		goto GRADIENT_FAIL;

	ValidatePicture(dst_picture);

	stops_count = src_picture->pSourcePict->radial.nstops + 2;

	/* Because the max value of nstops is unkown, so create a program
	   when nstops > LINEAR_LARGE_STOPS.*/
	if (stops_count <= RADIAL_SMALL_STOPS) {
		gradient_prog = glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][0];
	} else if (stops_count <= RADIAL_LARGE_STOPS) {
		gradient_prog = glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][1];
	} else {
		_glamor_create_radial_gradient_program(screen,
						       src_picture->pSourcePict->linear.nstops + 2,
						       1);
		gradient_prog = glamor_priv->gradient_prog[SHADER_GRADIENT_RADIAL][2];
	}

	/* Bind all the uniform vars .*/
	transform_mat_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "transform_mat");
	repeat_type_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "repeat_type");
	n_stop_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "n_stop");
	A_value_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "A_value");
	repeat_type_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "repeat_type");
	c1_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "c1");
	r1_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "r1");
	c2_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "c2");
	r2_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "r2");

	if (src_picture->pSourcePict->radial.nstops + 2 <= RADIAL_SMALL_STOPS) {
		stop0_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop0");
		stop1_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop1");
		stop2_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop2");
		stop3_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop3");
		stop4_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop4");
		stop5_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop5");
		stop6_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop6");
		stop7_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop7");

		stop_color0_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color0");
		stop_color1_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color1");
		stop_color2_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color2");
		stop_color3_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color3");
		stop_color4_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color4");
		stop_color5_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color5");
		stop_color6_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color6");
		stop_color7_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color7");
	} else {
		stops_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stops");
		stop_colors_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_colors");
	}

	dispatch->glUseProgram(gradient_prog);

	dispatch->glUniform1i(repeat_type_uniform_location, src_picture->repeatType);


	if (src_picture->transform) {
		_glamor_gradient_convert_trans_matrix(src_picture->transform,
		                                      transform_mat,
		                                      width, height, 0);
		dispatch->glUniformMatrix3fv(transform_mat_uniform_location,
		                             1, 1, &transform_mat[0][0]);
	} else {
		dispatch->glUniformMatrix3fv(transform_mat_uniform_location,
		                             1, 1, &identity_mat[0][0]);
	}

	if (!_glamor_gradient_set_pixmap_destination(screen, glamor_priv, dst_picture,
	                                             &xscale, &yscale, x_source, y_source,
	                                             vertices, tex_vertices, 0))
		goto GRADIENT_FAIL;

	/* Set all the stops and colors to shader. */
	if (stops_count > RADIAL_SMALL_STOPS) {
		stop_colors = malloc(4 * stops_count * sizeof(float));
		if (stop_colors == NULL) {
			ErrorF("Failed to allocate stop_colors memory.\n");
			goto GRADIENT_FAIL;
		}

		n_stops = malloc(stops_count * sizeof(float));
		if (n_stops == NULL) {
			ErrorF("Failed to allocate n_stops memory.\n");
			goto GRADIENT_FAIL;
		}
	} else {
		stop_colors = stop_colors_st;
		n_stops = n_stops_st;
	}

	count = _glamor_gradient_set_stops(src_picture, &src_picture->pSourcePict->gradient,
	                                   stop_colors, n_stops);

	if (src_picture->pSourcePict->linear.nstops + 2 <= RADIAL_SMALL_STOPS) {
		int j = 0;
		dispatch->glUniform4f(stop_color0_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color1_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color2_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color3_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color4_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color5_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color6_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color7_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);

		j = 0;
		dispatch->glUniform1f(stop0_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop1_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop2_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop3_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop4_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop5_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop6_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop7_uniform_location, n_stops[j++]);
		dispatch->glUniform1i(n_stop_uniform_location, count);
	} else {
		dispatch->glUniform4fv(stop_colors_uniform_location, count, stop_colors);
		dispatch->glUniform1fv(stops_uniform_location, count, n_stops);
		dispatch->glUniform1i(n_stop_uniform_location, count);
	}

	c1x = (float)pixman_fixed_to_double(src_picture->pSourcePict->radial.c1.x);
	c1y = (float)pixman_fixed_to_double(src_picture->pSourcePict->radial.c1.y);
	c2x = (float)pixman_fixed_to_double(src_picture->pSourcePict->radial.c2.x);
	c2y = (float)pixman_fixed_to_double(src_picture->pSourcePict->radial.c2.y);

	r1 = (float)pixman_fixed_to_double(src_picture->pSourcePict->radial.c1.radius);
	r2 = (float)pixman_fixed_to_double(src_picture->pSourcePict->radial.c2.radius);

	glamor_set_circle_centre(width, height, c1x, c1y, glamor_priv->yInverted, cxy);
	dispatch->glUniform2fv(c1_uniform_location, 1, cxy);
	dispatch->glUniform1f(r1_uniform_location, r1);

	glamor_set_circle_centre(width, height, c2x, c2y, glamor_priv->yInverted, cxy);
	dispatch->glUniform2fv(c2_uniform_location, 1, cxy);
	dispatch->glUniform1f(r2_uniform_location, r2);

	A_value = (c2x - c1x) * (c2x - c1x) + (c2y - c1y) * (c2y - c1y) - (r2 - r1) * (r2 - r1);
	dispatch->glUniform1f(A_value_uniform_location, A_value);

	DEBUGF("C1:(%f, %f) R1:%f\nC2:(%f, %f) R2:%f\nA = %f\n",
	       c1x, c1y, r1, c2x, c2y, r2, A_value);

	/* Now rendering. */
	dispatch->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

	/* Do the clear logic.*/
	if (stops_count > RADIAL_SMALL_STOPS) {
		free(n_stops);
		free(stop_colors);
	}

	dispatch->glBindBuffer(GL_ARRAY_BUFFER, 0);
	dispatch->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

	dispatch->glDisableVertexAttribArray(GLAMOR_VERTEX_POS);
	dispatch->glDisableVertexAttribArray(GLAMOR_VERTEX_SOURCE);
	dispatch->glUseProgram(0);

	glamor_put_dispatch(glamor_priv);
	return dst_picture;

GRADIENT_FAIL:
	if (dst_picture) {
		FreePicture(dst_picture, 0);
	}

	if (stops_count > RADIAL_SMALL_STOPS) {
		if (n_stops)
			free(n_stops);
		if (stop_colors)
			free(stop_colors);
	}

	dispatch->glBindBuffer(GL_ARRAY_BUFFER, 0);
	dispatch->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

	dispatch->glDisableVertexAttribArray(GLAMOR_VERTEX_POS);
	dispatch->glDisableVertexAttribArray(GLAMOR_VERTEX_SOURCE);
	dispatch->glUseProgram(0);
	glamor_put_dispatch(glamor_priv);
	return NULL;
}

PicturePtr
glamor_generate_linear_gradient_picture(ScreenPtr screen,
                                         PicturePtr src_picture,
                                         int x_source, int y_source,
                                         int width, int height,
                                         PictFormatShort format)
{
	glamor_screen_private *glamor_priv;
	glamor_gl_dispatch *dispatch;
	PicturePtr dst_picture = NULL;
	PixmapPtr pixmap = NULL;
	GLint gradient_prog = 0;
	int error;
	float pt_distance;
	float p1_distance;
	GLfloat cos_val;
	float tex_vertices[8];
	int stops_count = 0;
	GLfloat *stop_colors = NULL;
	GLfloat *n_stops = NULL;
	int count = 0;
	float slope;
	GLfloat xscale, yscale;
	GLfloat pt1[2], pt2[2];
	float vertices[8];
	float transform_mat[3][3];
	static const float identity_mat[3][3] = {{1.0, 0.0, 0.0},
	                                         {0.0, 1.0, 0.0},
	                                         {0.0, 0.0, 1.0}};
	GLfloat stop_colors_st[LINEAR_SMALL_STOPS*4];
	GLfloat n_stops_st[LINEAR_SMALL_STOPS];

	GLint transform_mat_uniform_location = 0;
	GLint n_stop_uniform_location = 0;
	GLint stops_uniform_location = 0;
	GLint stop0_uniform_location = 0;
	GLint stop1_uniform_location = 0;
	GLint stop2_uniform_location = 0;
	GLint stop3_uniform_location = 0;
	GLint stop4_uniform_location = 0;
	GLint stop5_uniform_location = 0;
	GLint stop6_uniform_location = 0;
	GLint stop7_uniform_location = 0;
	GLint stop_colors_uniform_location = 0;
	GLint stop_color0_uniform_location = 0;
	GLint stop_color1_uniform_location = 0;
	GLint stop_color2_uniform_location = 0;
	GLint stop_color3_uniform_location = 0;
	GLint stop_color4_uniform_location = 0;
	GLint stop_color5_uniform_location = 0;
	GLint stop_color6_uniform_location = 0;
	GLint stop_color7_uniform_location = 0;
	GLint pt_slope_uniform_location = 0;
	GLint repeat_type_uniform_location = 0;
	GLint hor_ver_uniform_location = 0;
	GLint cos_val_uniform_location = 0;
	GLint p1_distance_uniform_location = 0;
	GLint pt_distance_uniform_location = 0;

	glamor_priv = glamor_get_screen_private(screen);
	dispatch = glamor_get_dispatch(glamor_priv);

	/* Create a pixmap with VBO. */
	pixmap = glamor_create_pixmap(screen,
	                              width, height,
	                              PIXMAN_FORMAT_DEPTH(format),
	                              0);

	if (!pixmap)
		goto GRADIENT_FAIL;

	dst_picture = CreatePicture(0, &pixmap->drawable,
	                            PictureMatchFormat(screen,
	                                    PIXMAN_FORMAT_DEPTH(format), format),
	                            0, 0, serverClient, &error);

	/* Release the reference, picture will hold the last one. */
	glamor_destroy_pixmap(pixmap);

	if (!dst_picture)
		goto GRADIENT_FAIL;

	ValidatePicture(dst_picture);

	stops_count = src_picture->pSourcePict->linear.nstops + 2;

	/* Because the max value of nstops is unkown, so create a program
	   when nstops > LINEAR_LARGE_STOPS.*/
	if (stops_count <= LINEAR_SMALL_STOPS) {
		gradient_prog = glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][0];
	} else if (stops_count <= LINEAR_LARGE_STOPS) {
		gradient_prog = glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][1];
	} else {
		_glamor_create_linear_gradient_program(screen,
		        src_picture->pSourcePict->linear.nstops + 2, 1);
		gradient_prog = glamor_priv->gradient_prog[SHADER_GRADIENT_LINEAR][2];
	}

	/* Bind all the uniform vars .*/
	n_stop_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "n_stop");
	pt_slope_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "pt_slope");
	repeat_type_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "repeat_type");
	hor_ver_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "hor_ver");
	transform_mat_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "transform_mat");
	cos_val_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "cos_val");
	p1_distance_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "p1_distance");
	pt_distance_uniform_location =
	    dispatch->glGetUniformLocation(gradient_prog, "pt_distance");

	if (src_picture->pSourcePict->linear.nstops + 2 <= LINEAR_SMALL_STOPS) {
		stop0_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop0");
		stop1_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop1");
		stop2_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop2");
		stop3_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop3");
		stop4_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop4");
		stop5_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop5");
		stop6_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop6");
		stop7_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop7");

		stop_color0_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color0");
		stop_color1_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color1");
		stop_color2_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color2");
		stop_color3_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color3");
		stop_color4_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color4");
		stop_color5_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color5");
		stop_color6_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color6");
		stop_color7_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_color7");
	} else {
		stops_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stops");
		stop_colors_uniform_location =
		    dispatch->glGetUniformLocation(gradient_prog, "stop_colors");
	}

	dispatch->glUseProgram(gradient_prog);

	dispatch->glUniform1i(repeat_type_uniform_location, src_picture->repeatType);

	/* set the transform matrix. */
	if (src_picture->transform) {
		_glamor_gradient_convert_trans_matrix(src_picture->transform,
		                                      transform_mat,
		                                      width, height, 1);
		dispatch->glUniformMatrix3fv(transform_mat_uniform_location,
		                             1, 1, &transform_mat[0][0]);
	} else {
		dispatch->glUniformMatrix3fv(transform_mat_uniform_location,
		                             1, 1, &identity_mat[0][0]);
	}

	if (!_glamor_gradient_set_pixmap_destination(screen, glamor_priv, dst_picture,
	                                             &xscale, &yscale, x_source, y_source,
	                                             vertices, tex_vertices, 1))
		goto GRADIENT_FAIL;

	/* Normalize the PTs. */
	glamor_set_normalize_pt(xscale, yscale,
	                        pixman_fixed_to_double(src_picture->pSourcePict->linear.p1.x),
	                        pixman_fixed_to_double(src_picture->pSourcePict->linear.p1.y),
	                        glamor_priv->yInverted,
	                        pt1);
	DEBUGF("pt1:(%f, %f) ---> (%f %f)\n", pixman_fixed_to_double(src_picture->pSourcePict->linear.p1.x),
	       pixman_fixed_to_double(src_picture->pSourcePict->linear.p1.y), pt1[0], pt1[1]);

	glamor_set_normalize_pt(xscale, yscale,
	                        pixman_fixed_to_double(src_picture->pSourcePict->linear.p2.x),
	                        pixman_fixed_to_double(src_picture->pSourcePict->linear.p2.y),
	                        glamor_priv->yInverted,
	                        pt2);
	DEBUGF("pt2:(%f, %f) ---> (%f %f)\n", pixman_fixed_to_double(src_picture->pSourcePict->linear.p2.x),
	       pixman_fixed_to_double(src_picture->pSourcePict->linear.p2.y), pt2[0], pt2[1]);

	/* Set all the stops and colors to shader. */
	if (stops_count > LINEAR_SMALL_STOPS) {
		stop_colors = malloc(4 * stops_count * sizeof(float));
		if (stop_colors == NULL) {
			ErrorF("Failed to allocate stop_colors memory.\n");
			goto GRADIENT_FAIL;
		}

		n_stops = malloc(stops_count * sizeof(float));
		if (n_stops == NULL) {
			ErrorF("Failed to allocate n_stops memory.\n");
			goto GRADIENT_FAIL;
		}
	} else {
		stop_colors = stop_colors_st;
		n_stops = n_stops_st;
	}

	count = _glamor_gradient_set_stops(src_picture, &src_picture->pSourcePict->gradient,
	                                   stop_colors, n_stops);

	if (src_picture->pSourcePict->linear.nstops + 2 <= LINEAR_SMALL_STOPS) {
		int j = 0;
		dispatch->glUniform4f(stop_color0_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color1_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color2_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color3_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color4_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color5_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color6_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);
		j++;
		dispatch->glUniform4f(stop_color7_uniform_location,
		                      stop_colors[4*j+0], stop_colors[4*j+1],
		                      stop_colors[4*j+2], stop_colors[4*j+3]);

		j = 0;
		dispatch->glUniform1f(stop0_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop1_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop2_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop3_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop4_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop5_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop6_uniform_location, n_stops[j++]);
		dispatch->glUniform1f(stop7_uniform_location, n_stops[j++]);

		dispatch->glUniform1i(n_stop_uniform_location, count);
	} else {
		dispatch->glUniform4fv(stop_colors_uniform_location, count, stop_colors);
		dispatch->glUniform1fv(stops_uniform_location, count, n_stops);
		dispatch->glUniform1i(n_stop_uniform_location, count);
	}

	if (src_picture->pSourcePict->linear.p2.y ==
	              src_picture->pSourcePict->linear.p1.y) { // The horizontal case.
		dispatch->glUniform1i(hor_ver_uniform_location, 1);
		DEBUGF("p1.y: %f, p2.y: %f, enter the horizontal case\n",
		       pt1[1], pt2[1]);

		p1_distance = pt1[0];
		pt_distance = (pt2[0] - p1_distance);
		dispatch->glUniform1f(p1_distance_uniform_location, p1_distance);
		dispatch->glUniform1f(pt_distance_uniform_location, pt_distance);
	} else {
		/* The slope need to compute here. In shader, the viewport set will change
		   the orginal slope and the slope which is vertical to it will not be correct.*/
		slope = - (float)(src_picture->pSourcePict->linear.p2.x
				  - src_picture->pSourcePict->linear.p1.x) /
		          (float)(src_picture->pSourcePict->linear.p2.y
				  - src_picture->pSourcePict->linear.p1.y);
		slope = slope * yscale / xscale;
		dispatch->glUniform1f(pt_slope_uniform_location, slope);
		dispatch->glUniform1i(hor_ver_uniform_location, 0);

		cos_val = sqrt(1.0 / (slope * slope + 1.0));
		dispatch->glUniform1f(cos_val_uniform_location, cos_val);

		p1_distance = (pt1[1] - pt1[0] * slope) * cos_val;
		pt_distance = (pt2[1] - pt2[0] * slope) * cos_val - p1_distance;
		dispatch->glUniform1f(p1_distance_uniform_location, p1_distance);
		dispatch->glUniform1f(pt_distance_uniform_location, pt_distance);
	}

	/* Now rendering. */
	dispatch->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

	/* Do the clear logic.*/
	if (stops_count > LINEAR_SMALL_STOPS) {
		free(n_stops);
		free(stop_colors);
	}

	dispatch->glBindBuffer(GL_ARRAY_BUFFER, 0);
	dispatch->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

	dispatch->glDisableVertexAttribArray(GLAMOR_VERTEX_POS);
	dispatch->glDisableVertexAttribArray(GLAMOR_VERTEX_SOURCE);
	dispatch->glUseProgram(0);

	glamor_put_dispatch(glamor_priv);
	return dst_picture;

GRADIENT_FAIL:
	if (dst_picture) {
		FreePicture(dst_picture, 0);
	}

	if (stops_count > LINEAR_SMALL_STOPS) {
		if (n_stops)
			free(n_stops);
		if (stop_colors)
			free(stop_colors);
	}

	dispatch->glBindBuffer(GL_ARRAY_BUFFER, 0);
	dispatch->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

	dispatch->glDisableVertexAttribArray(GLAMOR_VERTEX_POS);
	dispatch->glDisableVertexAttribArray(GLAMOR_VERTEX_SOURCE);
	dispatch->glUseProgram(0);
	glamor_put_dispatch(glamor_priv);
	return NULL;
}

#endif /* End of GLAMOR_GRADIENT_SHADER */

#endif /* End of RENDER */