/* * 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. */ /** * \file buffers.c * glReadBuffer, DrawBuffer functions. */ #include "glheader.h" #include "buffers.h" #include "colormac.h" #include "context.h" #include "enums.h" #include "fbobject.h" #include "mtypes.h" #define BAD_MASK ~0u /** * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are * available to the rendering context (for drawing or reading). * This depends on the type of framebuffer. For window system framebuffers * we look at the framebuffer's visual. But for user-create framebuffers we * look at the number of supported color attachments. * \param fb the framebuffer to draw to, or read from * \return bitmask of BUFFER_BIT_* flags */ static GLbitfield supported_buffer_bitmask(const struct gl_context *ctx, const struct gl_framebuffer *fb) { GLbitfield mask = 0x0; if (_mesa_is_user_fbo(fb)) { /* A user-created renderbuffer */ GLuint i; for (i = 0; i < ctx->Const.MaxColorAttachments; i++) { mask |= (BUFFER_BIT_COLOR0 << i); } } else { /* A window system framebuffer */ GLint i; mask = BUFFER_BIT_FRONT_LEFT; /* always have this */ if (fb->Visual.stereoMode) { mask |= BUFFER_BIT_FRONT_RIGHT; if (fb->Visual.doubleBufferMode) { mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT; } } else if (fb->Visual.doubleBufferMode) { mask |= BUFFER_BIT_BACK_LEFT; } for (i = 0; i < fb->Visual.numAuxBuffers; i++) { mask |= (BUFFER_BIT_AUX0 << i); } } return mask; } /** * Helper routine used by glDrawBuffer and glDrawBuffersARB. * Given a GLenum naming one or more color buffers (such as * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags. */ static GLbitfield draw_buffer_enum_to_bitmask(const struct gl_context *ctx, GLenum buffer) { switch (buffer) { case GL_NONE: return 0; case GL_FRONT: return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT; case GL_BACK: if (_mesa_is_gles3(ctx)) { /* Page 181 (page 192 of the PDF) in section 4.2.1 of the OpenGL * ES 3.0.1 specification says: * * "When draw buffer zero is BACK, color values are written * into the sole buffer for single-buffered contexts, or into * the back buffer for double-buffered contexts." * * Since there is no stereo rendering in ES 3.0, only return the * LEFT bits. This also satisfies the "n must be 1" requirement. */ if (ctx->DrawBuffer->Visual.doubleBufferMode) return BUFFER_BIT_BACK_LEFT; return BUFFER_BIT_FRONT_LEFT; } return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT; case GL_RIGHT: return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT; case GL_FRONT_RIGHT: return BUFFER_BIT_FRONT_RIGHT; case GL_BACK_RIGHT: return BUFFER_BIT_BACK_RIGHT; case GL_BACK_LEFT: return BUFFER_BIT_BACK_LEFT; case GL_FRONT_AND_BACK: return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT; case GL_LEFT: return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT; case GL_FRONT_LEFT: return BUFFER_BIT_FRONT_LEFT; case GL_AUX0: return BUFFER_BIT_AUX0; case GL_AUX1: case GL_AUX2: case GL_AUX3: return 1 << BUFFER_COUNT; /* invalid, but not BAD_MASK */ case GL_COLOR_ATTACHMENT0_EXT: return BUFFER_BIT_COLOR0; case GL_COLOR_ATTACHMENT1_EXT: return BUFFER_BIT_COLOR1; case GL_COLOR_ATTACHMENT2_EXT: return BUFFER_BIT_COLOR2; case GL_COLOR_ATTACHMENT3_EXT: return BUFFER_BIT_COLOR3; case GL_COLOR_ATTACHMENT4_EXT: return BUFFER_BIT_COLOR4; case GL_COLOR_ATTACHMENT5_EXT: return BUFFER_BIT_COLOR5; case GL_COLOR_ATTACHMENT6_EXT: return BUFFER_BIT_COLOR6; case GL_COLOR_ATTACHMENT7_EXT: return BUFFER_BIT_COLOR7; default: /* error */ return BAD_MASK; } } /** * Helper routine used by glReadBuffer. * Given a GLenum naming a color buffer, return the index of the corresponding * renderbuffer (a BUFFER_* value). * return -1 for an invalid buffer. */ static GLint read_buffer_enum_to_index(GLenum buffer) { switch (buffer) { case GL_FRONT: return BUFFER_FRONT_LEFT; case GL_BACK: return BUFFER_BACK_LEFT; case GL_RIGHT: return BUFFER_FRONT_RIGHT; case GL_FRONT_RIGHT: return BUFFER_FRONT_RIGHT; case GL_BACK_RIGHT: return BUFFER_BACK_RIGHT; case GL_BACK_LEFT: return BUFFER_BACK_LEFT; case GL_LEFT: return BUFFER_FRONT_LEFT; case GL_FRONT_LEFT: return BUFFER_FRONT_LEFT; case GL_AUX0: return BUFFER_AUX0; case GL_AUX1: case GL_AUX2: case GL_AUX3: return BUFFER_COUNT; /* invalid, but not -1 */ case GL_COLOR_ATTACHMENT0_EXT: return BUFFER_COLOR0; case GL_COLOR_ATTACHMENT1_EXT: return BUFFER_COLOR1; case GL_COLOR_ATTACHMENT2_EXT: return BUFFER_COLOR2; case GL_COLOR_ATTACHMENT3_EXT: return BUFFER_COLOR3; case GL_COLOR_ATTACHMENT4_EXT: return BUFFER_COLOR4; case GL_COLOR_ATTACHMENT5_EXT: return BUFFER_COLOR5; case GL_COLOR_ATTACHMENT6_EXT: return BUFFER_COLOR6; case GL_COLOR_ATTACHMENT7_EXT: return BUFFER_COLOR7; default: /* error */ return -1; } } /** * Called by glDrawBuffer(). * Specify which renderbuffer(s) to draw into for the first color output. * can name zero, one, two or four renderbuffers! * \sa _mesa_DrawBuffers * * \param buffer buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc. * * Note that the behaviour of this function depends on whether the * current ctx->DrawBuffer is a window-system framebuffer or a user-created * framebuffer object. * In the former case, we update the per-context ctx->Color.DrawBuffer * state var _and_ the FB's ColorDrawBuffer state. * In the later case, we update the FB's ColorDrawBuffer state only. * * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the * new FB is a window system FB, we need to re-update the FB's * ColorDrawBuffer state to match the context. This is handled in * _mesa_update_framebuffer(). * * See the GL_EXT_framebuffer_object spec for more info. */ void GLAPIENTRY _mesa_DrawBuffer(GLenum buffer) { GLbitfield destMask; GET_CURRENT_CONTEXT(ctx); FLUSH_VERTICES(ctx, 0); if (MESA_VERBOSE & VERBOSE_API) { _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer)); } if (buffer == GL_NONE) { destMask = 0x0; } else { const GLbitfield supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer); destMask = draw_buffer_enum_to_bitmask(ctx, buffer); if (destMask == BAD_MASK) { /* totally bogus buffer */ _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer=0x%x)", buffer); return; } destMask &= supportedMask; if (destMask == 0x0) { /* none of the named color buffers exist! */ _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffer(buffer=0x%x)", buffer); return; } } /* if we get here, there's no error so set new state */ _mesa_drawbuffers(ctx, 1, &buffer, &destMask); /* * Call device driver function. */ if (ctx->Driver.DrawBuffers) ctx->Driver.DrawBuffers(ctx, 1, &buffer); else if (ctx->Driver.DrawBuffer) ctx->Driver.DrawBuffer(ctx, buffer); } /** * Called by glDrawBuffersARB; specifies the destination color renderbuffers * for N fragment program color outputs. * \sa _mesa_DrawBuffer * \param n number of outputs * \param buffers array [n] of renderbuffer names. Unlike glDrawBuffer, the * names cannot specify more than one buffer. For example, * GL_FRONT_AND_BACK is illegal. */ void GLAPIENTRY _mesa_DrawBuffers(GLsizei n, const GLenum *buffers) { GLint output; GLbitfield usedBufferMask, supportedMask; GLbitfield destMask[MAX_DRAW_BUFFERS]; GET_CURRENT_CONTEXT(ctx); FLUSH_VERTICES(ctx, 0); /* Turns out n==0 is a valid input that should not produce an error. * The remaining code below correctly handles the n==0 case. * * From the OpenGL 3.0 specification, page 258: * "An INVALID_VALUE error is generated if n is greater than * MAX_DRAW_BUFFERS." */ if (n < 0 || n > (GLsizei) ctx->Const.MaxDrawBuffers) { _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)"); return; } supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer); usedBufferMask = 0x0; /* From the ES 3.0 specification, page 180: * "If the GL is bound to the default framebuffer, then n must be 1 * and the constant must be BACK or NONE." */ if (_mesa_is_gles3(ctx) && _mesa_is_winsys_fbo(ctx->DrawBuffer) && (n != 1 || (buffers[0] != GL_NONE && buffers[0] != GL_BACK))) { _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffers(buffer)"); return; } /* complicated error checking... */ for (output = 0; output < n; output++) { if (buffers[output] == GL_NONE) { destMask[output] = 0x0; } else { /* Page 259 (page 275 of the PDF) in section 4.2.1 of the OpenGL 3.0 * spec (20080923) says: * * "If the GL is bound to a framebuffer object and DrawBuffers is * supplied with [...] COLOR_ATTACHMENTm where m is greater than * or equal to the value of MAX_COLOR_ATTACHMENTS, then the error * INVALID_OPERATION results." */ if (_mesa_is_user_fbo(ctx->DrawBuffer) && buffers[output] >= GL_COLOR_ATTACHMENT0 + ctx->Const.MaxDrawBuffers) { _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB(buffer)"); return; } destMask[output] = draw_buffer_enum_to_bitmask(ctx, buffers[output]); /* From the OpenGL 3.0 specification, page 258: * "Each buffer listed in bufs must be one of the values from tables * 4.5 or 4.6. Otherwise, an INVALID_ENUM error is generated. */ if (destMask[output] == BAD_MASK) { _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)"); return; } /* From the OpenGL 3.0 specification, page 259: * "For both the default framebuffer and framebuffer objects, the * constants FRONT, BACK, LEFT, RIGHT, and FRONT_AND_BACK are not * valid in the bufs array passed to DrawBuffers, and will result in * the error INVALID_OPERATION. This restriction is because these * constants may themselves refer to multiple buffers, as shown in * table 4.4." */ if (_mesa_bitcount(destMask[output]) > 1) { _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB(buffer)"); return; } /* From the OpenGL 3.0 specification, page 259: * "If the GL is bound to the default framebuffer and DrawBuffers is * supplied with a constant (other than NONE) that does not indicate * any of the color buffers allocated to the GL context by the window * system, the error INVALID_OPERATION will be generated. * * If the GL is bound to a framebuffer object and DrawBuffers is * supplied with a constant from table 4.6 [...] then the error * INVALID_OPERATION results." */ destMask[output] &= supportedMask; if (destMask[output] == 0) { _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB(unsupported buffer)"); return; } /* ES 3.0 is even more restrictive. From the ES 3.0 spec, page 180: * "If the GL is bound to a framebuffer object, the ith buffer listed * in bufs must be COLOR_ATTACHMENTi or NONE. [...] INVALID_OPERATION." */ if (_mesa_is_gles3(ctx) && _mesa_is_user_fbo(ctx->DrawBuffer) && buffers[output] != GL_NONE && buffers[output] != GL_COLOR_ATTACHMENT0 + output) { _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffers(buffer)"); return; } /* From the OpenGL 3.0 specification, page 258: * "Except for NONE, a buffer may not appear more than once in the * array pointed to by bufs. Specifying a buffer more then once will * result in the error INVALID_OPERATION." */ if (destMask[output] & usedBufferMask) { _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB(duplicated buffer)"); return; } /* update bitmask */ usedBufferMask |= destMask[output]; } } /* OK, if we get here, there were no errors so set the new state */ _mesa_drawbuffers(ctx, n, buffers, destMask); /* * Call device driver function. Note that n can be equal to 0, * in which case we don't want to reference buffers[0], which * may not be valid. */ if (ctx->Driver.DrawBuffers) ctx->Driver.DrawBuffers(ctx, n, buffers); else if (ctx->Driver.DrawBuffer) ctx->Driver.DrawBuffer(ctx, n > 0 ? buffers[0] : GL_NONE); } /** * Performs necessary state updates when _mesa_drawbuffers makes an * actual change. */ static void updated_drawbuffers(struct gl_context *ctx) { FLUSH_VERTICES(ctx, _NEW_BUFFERS); if (ctx->API == API_OPENGL_COMPAT && !ctx->Extensions.ARB_ES2_compatibility) { struct gl_framebuffer *fb = ctx->DrawBuffer; /* Flag the FBO as requiring validation. */ if (_mesa_is_user_fbo(fb)) { fb->_Status = 0; } } } /** * Helper function to set the GL_DRAW_BUFFER state in the context and * current FBO. Called via glDrawBuffer(), glDrawBuffersARB() * * All error checking will have been done prior to calling this function * so nothing should go wrong at this point. * * \param ctx current context * \param n number of color outputs to set * \param buffers array[n] of colorbuffer names, like GL_LEFT. * \param destMask array[n] of BUFFER_BIT_* bitmasks which correspond to the * colorbuffer names. (i.e. GL_FRONT_AND_BACK => * BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT). */ void _mesa_drawbuffers(struct gl_context *ctx, GLuint n, const GLenum *buffers, const GLbitfield *destMask) { struct gl_framebuffer *fb = ctx->DrawBuffer; GLbitfield mask[MAX_DRAW_BUFFERS]; GLuint buf; if (!destMask) { /* compute destMask values now */ const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb); GLuint output; for (output = 0; output < n; output++) { mask[output] = draw_buffer_enum_to_bitmask(ctx, buffers[output]); ASSERT(mask[output] != BAD_MASK); mask[output] &= supportedMask; } destMask = mask; } /* * If n==1, destMask[0] may have up to four bits set. * Otherwise, destMask[x] can only have one bit set. */ if (n == 1) { GLuint count = 0, destMask0 = destMask[0]; while (destMask0) { GLint bufIndex = ffs(destMask0) - 1; if (fb->_ColorDrawBufferIndexes[count] != bufIndex) { updated_drawbuffers(ctx); fb->_ColorDrawBufferIndexes[count] = bufIndex; } count++; destMask0 &= ~(1 << bufIndex); } fb->ColorDrawBuffer[0] = buffers[0]; fb->_NumColorDrawBuffers = count; } else { GLuint count = 0; for (buf = 0; buf < n; buf++ ) { if (destMask[buf]) { GLint bufIndex = ffs(destMask[buf]) - 1; /* only one bit should be set in the destMask[buf] field */ ASSERT(_mesa_bitcount(destMask[buf]) == 1); if (fb->_ColorDrawBufferIndexes[buf] != bufIndex) { updated_drawbuffers(ctx); fb->_ColorDrawBufferIndexes[buf] = bufIndex; } count = buf + 1; } else { if (fb->_ColorDrawBufferIndexes[buf] != -1) { updated_drawbuffers(ctx); fb->_ColorDrawBufferIndexes[buf] = -1; } } fb->ColorDrawBuffer[buf] = buffers[buf]; } fb->_NumColorDrawBuffers = count; } /* set remaining outputs to -1 (GL_NONE) */ for (buf = fb->_NumColorDrawBuffers; buf < ctx->Const.MaxDrawBuffers; buf++) { if (fb->_ColorDrawBufferIndexes[buf] != -1) { updated_drawbuffers(ctx); fb->_ColorDrawBufferIndexes[buf] = -1; } } for (buf = n; buf < ctx->Const.MaxDrawBuffers; buf++) { fb->ColorDrawBuffer[buf] = GL_NONE; } if (_mesa_is_winsys_fbo(fb)) { /* also set context drawbuffer state */ for (buf = 0; buf < ctx->Const.MaxDrawBuffers; buf++) { if (ctx->Color.DrawBuffer[buf] != fb->ColorDrawBuffer[buf]) { updated_drawbuffers(ctx); ctx->Color.DrawBuffer[buf] = fb->ColorDrawBuffer[buf]; } } } } /** * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc. * from the context's Color.DrawBuffer[] state. * Use when changing contexts. */ void _mesa_update_draw_buffers(struct gl_context *ctx) { GLenum buffers[MAX_DRAW_BUFFERS]; GLuint i; /* should be a window system FBO */ assert(_mesa_is_winsys_fbo(ctx->DrawBuffer)); for (i = 0; i < ctx->Const.MaxDrawBuffers; i++) buffers[i] = ctx->Color.DrawBuffer[i]; _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers, buffers, NULL); } /** * Like \sa _mesa_drawbuffers(), this is a helper function for setting * GL_READ_BUFFER state in the context and current FBO. * \param ctx the rendering context * \param buffer GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc. * \param bufferIndex the numerical index corresponding to 'buffer' */ void _mesa_readbuffer(struct gl_context *ctx, GLenum buffer, GLint bufferIndex) { struct gl_framebuffer *fb = ctx->ReadBuffer; if (_mesa_is_winsys_fbo(fb)) { /* Only update the per-context READ_BUFFER state if we're bound to * a window-system framebuffer. */ ctx->Pixel.ReadBuffer = buffer; } fb->ColorReadBuffer = buffer; fb->_ColorReadBufferIndex = bufferIndex; ctx->NewState |= _NEW_BUFFERS; } /** * Called by glReadBuffer to set the source renderbuffer for reading pixels. * \param mode color buffer such as GL_FRONT, GL_BACK, etc. */ void GLAPIENTRY _mesa_ReadBuffer(GLenum buffer) { struct gl_framebuffer *fb; GLbitfield supportedMask; GLint srcBuffer; GET_CURRENT_CONTEXT(ctx); FLUSH_VERTICES(ctx, 0); if (MESA_VERBOSE & VERBOSE_API) _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer)); fb = ctx->ReadBuffer; if (MESA_VERBOSE & VERBOSE_API) _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer)); if (buffer == GL_NONE) { /* This is legal--it means that no buffer should be bound for reading. */ srcBuffer = -1; } else { /* general case / window-system framebuffer */ srcBuffer = read_buffer_enum_to_index(buffer); if (srcBuffer == -1) { _mesa_error(ctx, GL_INVALID_ENUM, "glReadBuffer(buffer=0x%x)", buffer); return; } supportedMask = supported_buffer_bitmask(ctx, fb); if (((1 << srcBuffer) & supportedMask) == 0) { _mesa_error(ctx, GL_INVALID_OPERATION, "glReadBuffer(buffer=0x%x)", buffer); return; } } /* OK, all error checking has been completed now */ _mesa_readbuffer(ctx, buffer, srcBuffer); /* * Call device driver function. */ if (ctx->Driver.ReadBuffer) (*ctx->Driver.ReadBuffer)(ctx, buffer); }