/* * Mesa 3-D graphics library * * Copyright (C) 1999-2007 Brian Paul All Rights Reserved. * * 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 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. */ #include "main/glheader.h" #include "main/context.h" #include "main/imports.h" #include "main/format_pack.h" #include "main/format_unpack.h" #include "main/core.h" #include "main/stencil.h" #include "s_context.h" #include "s_depth.h" #include "s_stencil.h" #include "s_span.h" /* Stencil Logic: IF stencil test fails THEN Apply fail-op to stencil value Don't write the pixel (RGBA,Z) ELSE IF doing depth test && depth test fails THEN Apply zfail-op to stencil value Write RGBA and Z to appropriate buffers ELSE Apply zpass-op to stencil value ENDIF */ /** * Compute/return the offset of the stencil value in a pixel. * For example, if the format is Z24+S8, the position of the stencil bits * within the 4-byte pixel will be either 0 or 3. */ static GLint get_stencil_offset(gl_format format) { const GLubyte one = 1; GLubyte pixel[MAX_PIXEL_BYTES]; GLint bpp = _mesa_get_format_bytes(format); GLint i; assert(_mesa_get_format_bits(format, GL_STENCIL_BITS) == 8); memset(pixel, 0, sizeof(pixel)); _mesa_pack_ubyte_stencil_row(format, 1, &one, pixel); for (i = 0; i < bpp; i++) { if (pixel[i]) return i; } _mesa_problem(NULL, "get_stencil_offset() failed\n"); return 0; } /** Clamp the stencil value to [0, 255] */ static inline GLubyte clamp(GLint val) { if (val < 0) return 0; else if (val > 255) return 255; else return val; } #define STENCIL_OP(NEW_VAL) \ if (invmask == 0) { \ for (i = j = 0; i < n; i++, j += stride) { \ if (mask[i]) { \ GLubyte s = stencil[j]; \ (void) s; \ stencil[j] = (GLubyte) (NEW_VAL); \ } \ } \ } \ else { \ for (i = j = 0; i < n; i++, j += stride) { \ if (mask[i]) { \ GLubyte s = stencil[j]; \ stencil[j] = (GLubyte) ((invmask & s) | (wrtmask & (NEW_VAL))); \ } \ } \ } /** * Apply the given stencil operator to the array of stencil values. * Don't touch stencil[i] if mask[i] is zero. * @param n number of stencil values * @param oper the stencil buffer operator * @param face 0 or 1 for front or back face operation * @param stencil array of stencil values (in/out) * @param mask array [n] of flag: 1=apply operator, 0=don't apply operator * @param stride stride between stencil values */ static void apply_stencil_op(const struct gl_context *ctx, GLenum oper, GLuint face, GLuint n, GLubyte stencil[], const GLubyte mask[], GLint stride) { const GLubyte ref = _mesa_get_stencil_ref(ctx, face); const GLubyte wrtmask = ctx->Stencil.WriteMask[face]; const GLubyte invmask = (GLubyte) (~wrtmask); GLuint i, j; switch (oper) { case GL_KEEP: /* do nothing */ break; case GL_ZERO: /* replace stencil buf values with zero */ STENCIL_OP(0); break; case GL_REPLACE: /* replace stencil buf values with ref value */ STENCIL_OP(ref); break; case GL_INCR: /* increment stencil buf values, with clamping */ STENCIL_OP(clamp(s + 1)); break; case GL_DECR: /* increment stencil buf values, with clamping */ STENCIL_OP(clamp(s - 1)); break; case GL_INCR_WRAP_EXT: /* increment stencil buf values, without clamping */ STENCIL_OP(s + 1); break; case GL_DECR_WRAP_EXT: /* increment stencil buf values, without clamping */ STENCIL_OP(s - 1); break; case GL_INVERT: /* replace stencil buf values with inverted value */ STENCIL_OP(~s); break; default: _mesa_problem(ctx, "Bad stencil op in apply_stencil_op"); } } #define STENCIL_TEST(FUNC) \ for (i = j = 0; i < n; i++, j += stride) { \ if (mask[i]) { \ s = (GLubyte) (stencil[j] & valueMask); \ if (FUNC) { \ /* stencil pass */ \ fail[i] = 0; \ } \ else { \ /* stencil fail */ \ fail[i] = 1; \ mask[i] = 0; \ } \ } \ else { \ fail[i] = 0; \ } \ } /** * Apply stencil test to an array of stencil values (before depth buffering). * For the values that fail, we'll apply the GL_STENCIL_FAIL operator to * the stencil values. * * @param face 0 or 1 for front or back-face polygons * @param n number of pixels in the array * @param stencil array of [n] stencil values (in/out) * @param mask array [n] of flag: 0=skip the pixel, 1=stencil the pixel, * values are set to zero where the stencil test fails. * @param stride stride between stencil values * @return GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed. */ static GLboolean do_stencil_test(struct gl_context *ctx, GLuint face, GLuint n, GLubyte stencil[], GLubyte mask[], GLint stride) { SWcontext *swrast = SWRAST_CONTEXT(ctx); GLubyte *fail = swrast->stencil_temp.buf2; GLboolean allfail = GL_FALSE; GLuint i, j; const GLuint valueMask = ctx->Stencil.ValueMask[face]; const GLubyte ref = (GLubyte) (_mesa_get_stencil_ref(ctx, face) & valueMask); GLubyte s; /* * Perform stencil test. The results of this operation are stored * in the fail[] array: * IF fail[i] is non-zero THEN * the stencil fail operator is to be applied * ELSE * the stencil fail operator is not to be applied * ENDIF */ switch (ctx->Stencil.Function[face]) { case GL_NEVER: STENCIL_TEST(0); allfail = GL_TRUE; break; case GL_LESS: STENCIL_TEST(ref < s); break; case GL_LEQUAL: STENCIL_TEST(ref <= s); break; case GL_GREATER: STENCIL_TEST(ref > s); break; case GL_GEQUAL: STENCIL_TEST(ref >= s); break; case GL_EQUAL: STENCIL_TEST(ref == s); break; case GL_NOTEQUAL: STENCIL_TEST(ref != s); break; case GL_ALWAYS: STENCIL_TEST(1); break; default: _mesa_problem(ctx, "Bad stencil func in gl_stencil_span"); return 0; } if (ctx->Stencil.FailFunc[face] != GL_KEEP) { apply_stencil_op(ctx, ctx->Stencil.FailFunc[face], face, n, stencil, fail, stride); } return !allfail; } /** * Compute the zpass/zfail masks by comparing the pre- and post-depth test * masks. */ static inline void compute_pass_fail_masks(GLuint n, const GLubyte origMask[], const GLubyte newMask[], GLubyte passMask[], GLubyte failMask[]) { GLuint i; for (i = 0; i < n; i++) { ASSERT(newMask[i] == 0 || newMask[i] == 1); passMask[i] = origMask[i] & newMask[i]; failMask[i] = origMask[i] & (newMask[i] ^ 1); } } /** * Get 8-bit stencil values from random locations in the stencil buffer. */ static void get_s8_values(struct gl_context *ctx, struct gl_renderbuffer *rb, GLuint count, const GLint x[], const GLint y[], GLubyte stencil[]) { struct swrast_renderbuffer *srb = swrast_renderbuffer(rb); const GLint w = rb->Width, h = rb->Height; const GLubyte *map = _swrast_pixel_address(rb, 0, 0); GLuint i; if (rb->Format == MESA_FORMAT_S8) { const GLint rowStride = srb->RowStride; for (i = 0; i < count; i++) { if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) { stencil[i] = *(map + y[i] * rowStride + x[i]); } } } else { const GLint bpp = _mesa_get_format_bytes(rb->Format); const GLint rowStride = srb->RowStride; for (i = 0; i < count; i++) { if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) { const GLubyte *src = map + y[i] * rowStride + x[i] * bpp; _mesa_unpack_ubyte_stencil_row(rb->Format, 1, src, &stencil[i]); } } } } /** * Put 8-bit stencil values at random locations into the stencil buffer. */ static void put_s8_values(struct gl_context *ctx, struct gl_renderbuffer *rb, GLuint count, const GLint x[], const GLint y[], const GLubyte stencil[]) { const GLint w = rb->Width, h = rb->Height; gl_pack_ubyte_stencil_func pack_stencil = _mesa_get_pack_ubyte_stencil_func(rb->Format); GLuint i; for (i = 0; i < count; i++) { if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) { GLubyte *dst = _swrast_pixel_address(rb, x[i], y[i]); pack_stencil(&stencil[i], dst); } } } /** * /return GL_TRUE = one or more fragments passed, * GL_FALSE = all fragments failed. */ GLboolean _swrast_stencil_and_ztest_span(struct gl_context *ctx, SWspan *span) { SWcontext *swrast = SWRAST_CONTEXT(ctx); struct gl_framebuffer *fb = ctx->DrawBuffer; struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer; const GLint stencilOffset = get_stencil_offset(rb->Format); const GLint stencilStride = _mesa_get_format_bytes(rb->Format); const GLuint face = (span->facing == 0) ? 0 : ctx->Stencil._BackFace; const GLuint count = span->end; GLubyte *mask = span->array->mask; GLubyte *stencilTemp = swrast->stencil_temp.buf1; GLubyte *stencilBuf; if (span->arrayMask & SPAN_XY) { /* read stencil values from random locations */ get_s8_values(ctx, rb, count, span->array->x, span->array->y, stencilTemp); stencilBuf = stencilTemp; } else { /* Processing a horizontal run of pixels. Since stencil is always * 8 bits for all MESA_FORMATs, we just need to use the right offset * and stride to access them. */ stencilBuf = _swrast_pixel_address(rb, span->x, span->y) + stencilOffset; } /* * Apply the stencil test to the fragments. * failMask[i] is 1 if the stencil test failed. */ if (!do_stencil_test(ctx, face, count, stencilBuf, mask, stencilStride)) { /* all fragments failed the stencil test, we're done. */ span->writeAll = GL_FALSE; if (span->arrayMask & SPAN_XY) { /* need to write the updated stencil values back to the buffer */ put_s8_values(ctx, rb, count, span->array->x, span->array->y, stencilTemp); } return GL_FALSE; } /* * Some fragments passed the stencil test, apply depth test to them * and apply Zpass and Zfail stencil ops. */ if (ctx->Depth.Test == GL_FALSE || ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer == NULL) { /* * No depth buffer, just apply zpass stencil function to active pixels. */ apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face, count, stencilBuf, mask, stencilStride); } else { /* * Perform depth buffering, then apply zpass or zfail stencil function. */ SWcontext *swrast = SWRAST_CONTEXT(ctx); GLubyte *passMask = swrast->stencil_temp.buf2; GLubyte *failMask = swrast->stencil_temp.buf3; GLubyte *origMask = swrast->stencil_temp.buf4; /* save the current mask bits */ memcpy(origMask, mask, count * sizeof(GLubyte)); /* apply the depth test */ _swrast_depth_test_span(ctx, span); compute_pass_fail_masks(count, origMask, mask, passMask, failMask); /* apply the pass and fail operations */ if (ctx->Stencil.ZFailFunc[face] != GL_KEEP) { apply_stencil_op(ctx, ctx->Stencil.ZFailFunc[face], face, count, stencilBuf, failMask, stencilStride); } if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) { apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face, count, stencilBuf, passMask, stencilStride); } } /* Write updated stencil values back into hardware stencil buffer */ if (span->arrayMask & SPAN_XY) { put_s8_values(ctx, rb, count, span->array->x, span->array->y, stencilBuf); } span->writeAll = GL_FALSE; return GL_TRUE; /* one or more fragments passed both tests */ } /** * Return a span of stencil values from the stencil buffer. * Used for glRead/CopyPixels * Input: n - how many pixels * x,y - location of first pixel * Output: stencil - the array of stencil values */ void _swrast_read_stencil_span(struct gl_context *ctx, struct gl_renderbuffer *rb, GLint n, GLint x, GLint y, GLubyte stencil[]) { GLubyte *src; if (y < 0 || y >= (GLint) rb->Height || x + n <= 0 || x >= (GLint) rb->Width) { /* span is completely outside framebuffer */ return; /* undefined values OK */ } if (x < 0) { GLint dx = -x; x = 0; n -= dx; stencil += dx; } if (x + n > (GLint) rb->Width) { GLint dx = x + n - rb->Width; n -= dx; } if (n <= 0) { return; } src = _swrast_pixel_address(rb, x, y); _mesa_unpack_ubyte_stencil_row(rb->Format, n, src, stencil); } /** * Write a span of stencil values to the stencil buffer. This function * applies the stencil write mask when needed. * Used for glDraw/CopyPixels * Input: n - how many pixels * x, y - location of first pixel * stencil - the array of stencil values */ void _swrast_write_stencil_span(struct gl_context *ctx, GLint n, GLint x, GLint y, const GLubyte stencil[] ) { SWcontext *swrast = SWRAST_CONTEXT(ctx); struct gl_framebuffer *fb = ctx->DrawBuffer; struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer; const GLuint stencilMax = (1 << fb->Visual.stencilBits) - 1; const GLuint stencilMask = ctx->Stencil.WriteMask[0]; GLubyte *stencilBuf; if (y < 0 || y >= (GLint) rb->Height || x + n <= 0 || x >= (GLint) rb->Width) { /* span is completely outside framebuffer */ return; /* undefined values OK */ } if (x < 0) { GLint dx = -x; x = 0; n -= dx; stencil += dx; } if (x + n > (GLint) rb->Width) { GLint dx = x + n - rb->Width; n -= dx; } if (n <= 0) { return; } stencilBuf = _swrast_pixel_address(rb, x, y); if ((stencilMask & stencilMax) != stencilMax) { /* need to apply writemask */ GLubyte *destVals = swrast->stencil_temp.buf1; GLubyte *newVals = swrast->stencil_temp.buf2; GLint i; _mesa_unpack_ubyte_stencil_row(rb->Format, n, stencilBuf, destVals); for (i = 0; i < n; i++) { newVals[i] = (stencil[i] & stencilMask) | (destVals[i] & ~stencilMask); } _mesa_pack_ubyte_stencil_row(rb->Format, n, newVals, stencilBuf); } else { _mesa_pack_ubyte_stencil_row(rb->Format, n, stencil, stencilBuf); } } /** * Clear the stencil buffer. If the buffer is a combined * depth+stencil buffer, only the stencil bits will be touched. */ void _swrast_clear_stencil_buffer(struct gl_context *ctx) { struct gl_renderbuffer *rb = ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer; const GLubyte stencilBits = ctx->DrawBuffer->Visual.stencilBits; const GLuint writeMask = ctx->Stencil.WriteMask[0]; const GLuint stencilMax = (1 << stencilBits) - 1; GLint x, y, width, height; GLubyte *map; GLint rowStride, i, j; GLbitfield mapMode; if (!rb || writeMask == 0) return; /* compute region to clear */ x = ctx->DrawBuffer->_Xmin; y = ctx->DrawBuffer->_Ymin; width = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin; height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin; mapMode = GL_MAP_WRITE_BIT; if ((writeMask & stencilMax) != stencilMax) { /* need to mask stencil values */ mapMode |= GL_MAP_READ_BIT; } else if (_mesa_get_format_bits(rb->Format, GL_DEPTH_BITS) > 0) { /* combined depth+stencil, need to mask Z values */ mapMode |= GL_MAP_READ_BIT; } ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, mapMode, &map, &rowStride); if (!map) { _mesa_error(ctx, GL_OUT_OF_MEMORY, "glClear(stencil)"); return; } switch (rb->Format) { case MESA_FORMAT_S8: { GLubyte clear = ctx->Stencil.Clear & writeMask & 0xff; GLubyte mask = (~writeMask) & 0xff; if (mask != 0) { /* masked clear */ for (i = 0; i < height; i++) { GLubyte *row = map; for (j = 0; j < width; j++) { row[j] = (row[j] & mask) | clear; } map += rowStride; } } else if (rowStride == width) { /* clear whole buffer */ memset(map, clear, width * height); } else { /* clear scissored */ for (i = 0; i < height; i++) { memset(map, clear, width); map += rowStride; } } } break; case MESA_FORMAT_S8_Z24: { GLuint clear = (ctx->Stencil.Clear & writeMask & 0xff) << 24; GLuint mask = (((~writeMask) & 0xff) << 24) | 0xffffff; for (i = 0; i < height; i++) { GLuint *row = (GLuint *) map; for (j = 0; j < width; j++) { row[j] = (row[j] & mask) | clear; } map += rowStride; } } break; case MESA_FORMAT_Z24_S8: { GLuint clear = ctx->Stencil.Clear & writeMask & 0xff; GLuint mask = 0xffffff00 | ((~writeMask) & 0xff); for (i = 0; i < height; i++) { GLuint *row = (GLuint *) map; for (j = 0; j < width; j++) { row[j] = (row[j] & mask) | clear; } map += rowStride; } } break; default: _mesa_problem(ctx, "Unexpected stencil buffer format %s" " in _swrast_clear_stencil_buffer()", _mesa_get_format_name(rb->Format)); } ctx->Driver.UnmapRenderbuffer(ctx, rb); }