From fd3891cbbe8f11c297edf0a6bf0580f69024722e Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Tue, 18 Dec 2012 13:26:03 -0800 Subject: [PATCH] mesa: Handle GL_BACK correctly for ES 3.0 in glDrawBuffers(). In ES 3.0, when calling glDrawBuffers() on the window system framebuffer, the only valid targets are GL_NONE or GL_BACK. Since there is no stereo rendering in ES 3.0, this is a single buffer, unlike desktop where it may be two (and thus isn't allowed). For single-buffered configs, GL_BACK ironically means the front (and only) buffer. I'm not sure that it matters, however, as ES shouldn't have front buffer rendering in the first place. Fixes es3conform framebuffer_blit_coverage_default_draw_buffer_binding. v2: Update GLES3 spec reference. Signed-off-by: Anuj Phogat Signed-off-by: Kenneth Graunke Signed-off-by: Ian Romanick [v2] Reviewed-by: Anuj Phogat Reviewed-by: Ian Romanick [v1] --- src/mesa/main/buffers.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/src/mesa/main/buffers.c b/src/mesa/main/buffers.c index 3dcd46f0180..b4f324c6c91 100644 --- a/src/mesa/main/buffers.c +++ b/src/mesa/main/buffers.c @@ -94,7 +94,7 @@ supported_buffer_bitmask(const struct gl_context *ctx, * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags. */ static GLbitfield -draw_buffer_enum_to_bitmask(GLenum buffer) +draw_buffer_enum_to_bitmask(const struct gl_context *ctx, GLenum buffer) { switch (buffer) { case GL_NONE: @@ -102,6 +102,21 @@ draw_buffer_enum_to_bitmask(GLenum buffer) 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; @@ -241,7 +256,7 @@ _mesa_DrawBuffer(GLenum buffer) else { const GLbitfield supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer); - destMask = draw_buffer_enum_to_bitmask(buffer); + destMask = draw_buffer_enum_to_bitmask(ctx, buffer); if (destMask == BAD_MASK) { /* totally bogus buffer */ _mesa_error(ctx, GL_INVALID_ENUM, @@ -321,7 +336,7 @@ _mesa_DrawBuffers(GLsizei n, const GLenum *buffers) return; } - destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]); + 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 @@ -451,7 +466,7 @@ _mesa_drawbuffers(struct gl_context *ctx, GLuint n, const GLenum *buffers, const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb); GLuint output; for (output = 0; output < n; output++) { - mask[output] = draw_buffer_enum_to_bitmask(buffers[output]); + mask[output] = draw_buffer_enum_to_bitmask(ctx, buffers[output]); ASSERT(mask[output] != BAD_MASK); mask[output] &= supportedMask; } -- 2.30.2