mesa: Remove support for GL_EXT_blend_logic_op

Support is removed for four reasons:

1. The implementation was broken with respect to separate blend
equations.  The GL_EXT_blend_equation_separate spec says:

    "If EXT_blend_logic_op and EXT_blend_equation_separate are both
    supported, the logic op blend equation should be supported separately
    for RGB and alpha as with the other blend equation modes."

But Mesa's implementation of GL_LOGIC_OP specifically forbids this.

2. No hardware supported by Mesa can support separate blend equations
involving GL_LOGIC_OP.

3. No applications could be found that use this extension.

4. No other Linux OpenGL drivers support this extension.

Signed-off-by: Ian Romanick <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>
Cc: Brian Paul <[email protected]>

1 files changed, 7 insertions, 12 deletions

diff --git a/src/mesa/main/blend.c b/src/mesa/main/blend.c
index 4214a661bb8..4dcc0b9d2a3 100644
--- a/src/mesa/main/blend.c
+++ b/src/mesa/main/blend.c
@@ -285,8 +285,7 @@ _mesa_BlendFuncSeparatei(GLuint buf, GLenum sfactorRGB, GLenum dfactorRGB,
  * \return GL_TRUE if legal, GL_FALSE otherwise.
  */
 static GLboolean
-legal_blend_equation(const struct gl_context *ctx,
-                     GLenum mode, GLboolean is_separate)
+legal_blend_equation(const struct gl_context *ctx, GLenum mode)
 {
    switch (mode) {
    case GL_FUNC_ADD:
@@ -294,10 +293,6 @@ legal_blend_equation(const struct gl_context *ctx,
    case GL_MIN:
    case GL_MAX:
       return ctx->Extensions.EXT_blend_minmax;
-   case GL_LOGIC_OP:
-      /* glBlendEquationSeparate cannot take GL_LOGIC_OP as a parameter.
-       */
-      return ctx->Extensions.EXT_blend_logic_op && !is_separate;
    case GL_FUNC_SUBTRACT:
    case GL_FUNC_REVERSE_SUBTRACT:
       return ctx->Extensions.EXT_blend_subtract;
@@ -320,7 +315,7 @@ _mesa_BlendEquation( GLenum mode )
       _mesa_debug(ctx, "glBlendEquation(%s)\n",
                   _mesa_lookup_enum_by_nr(mode));
 
-   if (!legal_blend_equation(ctx, mode, GL_FALSE)) {
+   if (!legal_blend_equation(ctx, mode)) {
       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquation");
       return;
    }
@@ -370,7 +365,7 @@ _mesa_BlendEquationi(GLuint buf, GLenum mode)
       return;
    }
 
-   if (!legal_blend_equation(ctx, mode, GL_FALSE)) {
+   if (!legal_blend_equation(ctx, mode)) {
       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationi");
       return;
    }
@@ -408,12 +403,12 @@ _mesa_BlendEquationSeparateEXT( GLenum modeRGB, GLenum modeA )
       return;
    }
 
-   if (!legal_blend_equation(ctx, modeRGB, GL_TRUE)) {
+   if (!legal_blend_equation(ctx, modeRGB)) {
       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparateEXT(modeRGB)");
       return;
    }
 
-   if (!legal_blend_equation(ctx, modeA, GL_TRUE)) {
+   if (!legal_blend_equation(ctx, modeA)) {
       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparateEXT(modeA)");
       return;
    }
@@ -464,12 +459,12 @@ _mesa_BlendEquationSeparatei(GLuint buf, GLenum modeRGB, GLenum modeA)
       return;
    }
 
-   if (!legal_blend_equation(ctx, modeRGB, GL_TRUE)) {
+   if (!legal_blend_equation(ctx, modeRGB)) {
       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparatei(modeRGB)");
       return;
    }
 
-   if (!legal_blend_equation(ctx, modeA, GL_TRUE)) {
+   if (!legal_blend_equation(ctx, modeA)) {
       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparatei(modeA)");
       return;
    }