/*
* 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.
* <buffer> 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);
}