On 28/04/15 23:16, Brian Paul wrote:
If the user requested a GL_RGB texture but the driver actually allocated an RGBA texture, the alpha values in the texture may not be defined.If we later bind the texture as a color target and try to blend into it with GL_DST_ALPHA or GL_ONE_MINUS_DST_ALPHA we may blend with undefined alpha values when, in fact, the dest alpha value should be one. So replace GL_DST_ALPHA/GL_ONE_MINUS_DST_ALPHA with GL_ONE/GL_ZERO. Fixes the piglit fbo-blending-formats test for some GL_RGB formats with the VMware driver. Also tested with llvmpipe. --- src/mesa/state_tracker/st_atom_blend.c | 38 +++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 10 deletions(-) diff --git a/src/mesa/state_tracker/st_atom_blend.c b/src/mesa/state_tracker/st_atom_blend.c index 6bb4077..30bff7a 100644 --- a/src/mesa/state_tracker/st_atom_blend.c +++ b/src/mesa/state_tracker/st_atom_blend.c @@ -44,10 +44,21 @@ /** * Convert GLenum blend tokens to pipe tokens. * Both blend factors and blend funcs are accepted. + * \param destBaseFormat the base format of the render target, such as + * GL_RGBA, GL_RGB, GL_RED, GL_ALPHA, etc. */ static GLuint -translate_blend(GLenum blend) +translate_blend(GLenum blend, GLenum destBaseFormat) { + /* If we don't have destination alpha and the blend factor is either + * GL_DST_ALPHA or GL_ONE_MINUS_DST_ALPHA then we use + * PIPE_BLENDFACTOR_ONE or _ZERO instead. + */ + const bool haveDstA = (destBaseFormat == GL_RGBA || + destBaseFormat == GL_ALPHA || + destBaseFormat == GL_INTENSITY || + destBaseFormat == GL_LUMINANCE_ALPHA); + switch (blend) { /* blend functions */ case GL_FUNC_ADD: @@ -69,7 +80,7 @@ translate_blend(GLenum blend) case GL_SRC_ALPHA: return PIPE_BLENDFACTOR_SRC_ALPHA; case GL_DST_ALPHA: - return PIPE_BLENDFACTOR_DST_ALPHA; + return haveDstA ? PIPE_BLENDFACTOR_DST_ALPHA : PIPE_BLENDFACTOR_ONE; case GL_DST_COLOR: return PIPE_BLENDFACTOR_DST_COLOR; case GL_SRC_ALPHA_SATURATE: @@ -91,7 +102,7 @@ translate_blend(GLenum blend) case GL_ONE_MINUS_DST_COLOR: return PIPE_BLENDFACTOR_INV_DST_COLOR; case GL_ONE_MINUS_DST_ALPHA: - return PIPE_BLENDFACTOR_INV_DST_ALPHA; + return haveDstA ? PIPE_BLENDFACTOR_INV_DST_ALPHA : PIPE_BLENDFACTOR_ZERO; case GL_ONE_MINUS_CONSTANT_COLOR: return PIPE_BLENDFACTOR_INV_CONST_COLOR; case GL_ONE_MINUS_CONSTANT_ALPHA: @@ -208,14 +219,21 @@ update_blend( struct st_context *st ) else if (ctx->Color.BlendEnabled) { /* blending enabled */ for (i = 0, j = 0; i < num_state; i++) { + const struct gl_renderbuffer *rb; + GLenum baseFormat; blend->rt[i].blend_enable = (ctx->Color.BlendEnabled >> i) & 0x1; if (ctx->Extensions.ARB_draw_buffers_blend) j = i; + /* _NEW_BUFFERS */ + /* Get the base format of the render target */ + rb = ctx->DrawBuffer->_ColorDrawBuffers[j]; + baseFormat = rb ? rb->_BaseFormat : GL_RGBA; + blend->rt[i].rgb_func = - translate_blend(ctx->Color.Blend[j].EquationRGB); + translate_blend(ctx->Color.Blend[j].EquationRGB, baseFormat); if (ctx->Color.Blend[i].EquationRGB == GL_MIN || ctx->Color.Blend[i].EquationRGB == GL_MAX) { @@ -225,13 +243,13 @@ update_blend( struct st_context *st ) } else { blend->rt[i].rgb_src_factor = - translate_blend(ctx->Color.Blend[j].SrcRGB); + translate_blend(ctx->Color.Blend[j].SrcRGB, baseFormat); blend->rt[i].rgb_dst_factor = - translate_blend(ctx->Color.Blend[j].DstRGB); + translate_blend(ctx->Color.Blend[j].DstRGB, baseFormat); } blend->rt[i].alpha_func = - translate_blend(ctx->Color.Blend[j].EquationA); + translate_blend(ctx->Color.Blend[j].EquationA, baseFormat); if (ctx->Color.Blend[i].EquationA == GL_MIN || ctx->Color.Blend[i].EquationA == GL_MAX) { @@ -241,9 +259,9 @@ update_blend( struct st_context *st ) } else { blend->rt[i].alpha_src_factor = - translate_blend(ctx->Color.Blend[j].SrcA); + translate_blend(ctx->Color.Blend[j].SrcA, baseFormat); blend->rt[i].alpha_dst_factor = - translate_blend(ctx->Color.Blend[j].DstA); + translate_blend(ctx->Color.Blend[j].DstA, baseFormat); } } } @@ -285,7 +303,7 @@ update_blend( struct st_context *st ) const struct st_tracked_state st_update_blend = { "st_update_blend", /* name */ { /* dirty */ - (_NEW_COLOR | _NEW_MULTISAMPLE), /* XXX _NEW_BLEND someday? */ /* mesa */ + (_NEW_BUFFERS | _NEW_COLOR | _NEW_MULTISAMPLE), /* mesa */ 0, /* st */ }, update_blend, /* update */
Series LGTM. Reviewed-by: Jose Fonseca <jfons...@vmware.com> _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
