1 files changed, 77 insertions, 5 deletions

diff --git a/mesalib/src/mesa/main/blend.c b/mesalib/src/mesa/main/blend.c
index 309f1d538..09a1c9ae8 100644
--- a/mesalib/src/mesa/main/blend.c
+++ b/mesalib/src/mesa/main/blend.c
@@ -765,24 +765,96 @@ _mesa_ClampColor(GLenum target, GLenum clamp)
 
    switch (target) {
    case GL_CLAMP_VERTEX_COLOR_ARB:
+      if (ctx->API == API_OPENGL_CORE &&
+          !ctx->Extensions.ARB_color_buffer_float) {
+         goto invalid_enum;
+      }
       FLUSH_VERTICES(ctx, _NEW_LIGHT);
       ctx->Light.ClampVertexColor = clamp;
+      _mesa_update_clamp_vertex_color(ctx);
       break;
    case GL_CLAMP_FRAGMENT_COLOR_ARB:
+      if (ctx->API == API_OPENGL_CORE &&
+          !ctx->Extensions.ARB_color_buffer_float) {
+         goto invalid_enum;
+      }
       FLUSH_VERTICES(ctx, _NEW_FRAG_CLAMP);
       ctx->Color.ClampFragmentColor = clamp;
+      _mesa_update_clamp_fragment_color(ctx);
       break;
    case GL_CLAMP_READ_COLOR_ARB:
       FLUSH_VERTICES(ctx, _NEW_COLOR);
       ctx->Color.ClampReadColor = clamp;
       break;
    default:
-      _mesa_error(ctx, GL_INVALID_ENUM, "glClampColorARB(target)");
-      return;
+      goto invalid_enum;
    }
+   return;
+
+invalid_enum:
+   _mesa_error(ctx, GL_INVALID_ENUM, "glClampColor(%s)",
+               _mesa_lookup_enum_by_nr(target));
+}
+
+static GLboolean
+get_clamp_color(const struct gl_framebuffer *fb, GLenum clamp)
+{
+   if (clamp == GL_TRUE || clamp == GL_FALSE)
+      return clamp;
+
+   ASSERT(clamp == GL_FIXED_ONLY);
+   if (!fb)
+      return GL_TRUE;
+
+   return fb->_AllColorBuffersFixedPoint;
+}
+
+GLboolean
+_mesa_get_clamp_fragment_color(const struct gl_context *ctx)
+{
+   return get_clamp_color(ctx->DrawBuffer,
+                                ctx->Color.ClampFragmentColor);
+}
+
+GLboolean
+_mesa_get_clamp_vertex_color(const struct gl_context *ctx)
+{
+   return get_clamp_color(ctx->DrawBuffer, ctx->Light.ClampVertexColor);
+}
+
+GLboolean
+_mesa_get_clamp_read_color(const struct gl_context *ctx)
+{
+   return get_clamp_color(ctx->ReadBuffer, ctx->Color.ClampReadColor);
 }
 
+/**
+ * Update the ctx->Color._ClampFragmentColor field
+ */
+void
+_mesa_update_clamp_fragment_color(struct gl_context *ctx)
+{
+   struct gl_framebuffer *fb = ctx->DrawBuffer;
 
+   /* Don't clamp if:
+    * - there is no colorbuffer
+    * - all colorbuffers are unsigned normalized, so clamping has no effect
+    * - there is an integer colorbuffer
+    */
+   if (!fb || !fb->_HasSNormOrFloatColorBuffer || fb->_IntegerColor)
+      ctx->Color._ClampFragmentColor = GL_FALSE;
+   else
+      ctx->Color._ClampFragmentColor = _mesa_get_clamp_fragment_color(ctx);
+}
+
+/**
+ * Update the ctx->Color._ClampVertexColor field
+ */
+void
+_mesa_update_clamp_vertex_color(struct gl_context *ctx)
+{
+   ctx->Light._ClampVertexColor = _mesa_get_clamp_vertex_color(ctx);
+}
 
 
 /**********************************************************************/
@@ -832,10 +904,10 @@ void _mesa_init_color( struct gl_context * ctx )
       ctx->Color.DrawBuffer[0] = GL_FRONT;
    }
 
-   ctx->Color.ClampFragmentColor = GL_FIXED_ONLY_ARB;
-   ctx->Color._ClampFragmentColor = GL_TRUE;
+   ctx->Color.ClampFragmentColor = ctx->API == API_OPENGL_COMPAT ?
+                                   GL_FIXED_ONLY_ARB : GL_FALSE;
+   ctx->Color._ClampFragmentColor = GL_FALSE;
    ctx->Color.ClampReadColor = GL_FIXED_ONLY_ARB;
-   ctx->Color._ClampReadColor = GL_TRUE;
 
    if (ctx->API == API_OPENGLES2) {
       /* GLES 3 behaves as though GL_FRAMEBUFFER_SRGB is always enabled. */