mesa: don't set _ClampFragmentColor to TRUE if it has no effect

This should reduce shader recompilations with drivers that emulate fragment
color clamping, because we want the clamping to be enabled only if there is
a signed normalized or floating-point colorbuffer.

Reviewed-by: Brian Paul <[email protected]>

8 files changed, 29 insertions, 9 deletions

diff --git a/src/mesa/main/blend.c b/src/mesa/main/blend.c
index 88bf3654c10..15b0dc759cd 100644
--- a/src/mesa/main/blend.c
+++ b/src/mesa/main/blend.c
@@ -863,7 +863,7 @@ void _mesa_init_color( struct gl_context * ctx )
    }
 
    ctx->Color.ClampFragmentColor = GL_FIXED_ONLY_ARB;
-   ctx->Color._ClampFragmentColor = GL_TRUE;
+   ctx->Color._ClampFragmentColor = GL_FALSE;
    ctx->Color.ClampReadColor = GL_FIXED_ONLY_ARB;
 
    if (ctx->API == API_OPENGLES2) {
diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index 67c116163db..fc2b2620bbf 100644
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -785,6 +785,7 @@ _mesa_test_framebuffer_completeness(struct gl_context *ctx,
    fb->Width = 0;
    fb->Height = 0;
    fb->_AllColorBuffersFixedPoint = GL_TRUE;
+   fb->_HasSNormOrFloatColorBuffer = GL_FALSE;
 
    /* Start at -2 to more easily loop over all attachment points.
     *  -2: depth buffer
@@ -901,13 +902,17 @@ _mesa_test_framebuffer_completeness(struct gl_context *ctx,
       /* check if integer color */
       fb->_IntegerColor = _mesa_is_format_integer_color(attFormat);
 
-      /* Update _AllColorBuffersFixedPoint. */
+      /* Update _AllColorBuffersFixedPoint and _HasSNormOrFloatColorBuffer. */
       if (i >= 0) {
          GLenum type = _mesa_get_format_datatype(attFormat);
 
          fb->_AllColorBuffersFixedPoint =
             fb->_AllColorBuffersFixedPoint &&
             (type == GL_UNSIGNED_NORMALIZED || type == GL_SIGNED_NORMALIZED);
+
+         fb->_HasSNormOrFloatColorBuffer =
+            fb->_HasSNormOrFloatColorBuffer ||
+            type == GL_SIGNED_NORMALIZED || type == GL_FLOAT;
       }
 
       /* Error-check width, height, format */
diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
index 5fb36776b45..757c4b055d1 100644
--- a/src/mesa/main/framebuffer.c
+++ b/src/mesa/main/framebuffer.c
@@ -155,6 +155,7 @@ _mesa_initialize_window_framebuffer(struct gl_framebuffer *fb,
    fb->Delete = _mesa_destroy_framebuffer;
    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
    fb->_AllColorBuffersFixedPoint = !visual->floatMode;
+   fb->_HasSNormOrFloatColorBuffer = visual->floatMode;
 
    compute_depth_max(fb);
 }
diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index 582ef319806..244e3ead6e7 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -24,6 +24,7 @@
 
 #include "glheader.h"
 #include "context.h"
+#include "blend.h"
 #include "enable.h"
 #include "enums.h"
 #include "extensions.h"
@@ -767,13 +768,13 @@ find_custom_value(struct gl_context *ctx, const struct value_desc *d, union valu
       break;
 
    case GL_FOG_COLOR:
-      if(ctx->Color._ClampFragmentColor)
+      if (_mesa_get_clamp_fragment_color(ctx))
          COPY_4FV(v->value_float_4, ctx->Fog.Color);
       else
          COPY_4FV(v->value_float_4, ctx->Fog.ColorUnclamped);
       break;
    case GL_COLOR_CLEAR_VALUE:
-      if(ctx->Color._ClampFragmentColor) {
+      if (_mesa_get_clamp_fragment_color(ctx)) {
          v->value_float_4[0] = CLAMP(ctx->Color.ClearColor.f[0], 0.0F, 1.0F);
          v->value_float_4[1] = CLAMP(ctx->Color.ClearColor.f[1], 0.0F, 1.0F);
          v->value_float_4[2] = CLAMP(ctx->Color.ClearColor.f[2], 0.0F, 1.0F);
@@ -782,13 +783,13 @@ find_custom_value(struct gl_context *ctx, const struct value_desc *d, union valu
          COPY_4FV(v->value_float_4, ctx->Color.ClearColor.f);
       break;
    case GL_BLEND_COLOR_EXT:
-      if(ctx->Color._ClampFragmentColor)
+      if (_mesa_get_clamp_fragment_color(ctx))
          COPY_4FV(v->value_float_4, ctx->Color.BlendColor);
       else
          COPY_4FV(v->value_float_4, ctx->Color.BlendColorUnclamped);
       break;
    case GL_ALPHA_TEST_REF:
-      if(ctx->Color._ClampFragmentColor)
+      if (_mesa_get_clamp_fragment_color(ctx))
          v->value_float = ctx->Color.AlphaRef;
       else
          v->value_float = ctx->Color.AlphaRefUnclamped;
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 40a567620ee..008f68bda08 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2662,6 +2662,7 @@ struct gl_framebuffer
 
    /* ARB_color_buffer_float */
    GLboolean _AllColorBuffersFixedPoint; /* no integer, no float */
+   GLboolean _HasSNormOrFloatColorBuffer;
 
    /** Array of all renderbuffer attachments, indexed by BUFFER_* tokens. */
    struct gl_renderbuffer_attachment Attachment[BUFFER_COUNT];
diff --git a/src/mesa/main/state.c b/src/mesa/main/state.c
index c94a2449930..73c5a1c263f 100644
--- a/src/mesa/main/state.c
+++ b/src/mesa/main/state.c
@@ -314,7 +314,17 @@ update_multisample(struct gl_context *ctx)
 static void
 update_clamp_fragment_color(struct gl_context *ctx)
 {
-   ctx->Color._ClampFragmentColor = _mesa_get_clamp_fragment_color(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);
 }
 
 
diff --git a/src/mesa/main/texenv.c b/src/mesa/main/texenv.c
index 0fe5fbd7a64..2979e6706e3 100644
--- a/src/mesa/main/texenv.c
+++ b/src/mesa/main/texenv.c
@@ -32,6 +32,7 @@
 
 #include "main/glheader.h"
 #include "main/context.h"
+#include "main/blend.h"
 #include "main/enums.h"
 #include "main/macros.h"
 #include "main/mtypes.h"
@@ -680,7 +681,7 @@ _mesa_GetTexEnvfv( GLenum target, GLenum pname, GLfloat *params )
       if (pname == GL_TEXTURE_ENV_COLOR) {
          if(ctx->NewState & (_NEW_BUFFERS | _NEW_FRAG_CLAMP))
             _mesa_update_state(ctx);
-         if(ctx->Color._ClampFragmentColor)
+         if (_mesa_get_clamp_fragment_color(ctx))
             COPY_4FV( params, texUnit->EnvColor );
          else
             COPY_4FV( params, texUnit->EnvColorUnclamped );
diff --git a/src/mesa/main/texparam.c b/src/mesa/main/texparam.c
index 898eabd3b0d..f60eb204e28 100644
--- a/src/mesa/main/texparam.c
+++ b/src/mesa/main/texparam.c
@@ -31,6 +31,7 @@
 
 #include <stdbool.h>
 #include "main/glheader.h"
+#include "main/blend.h"
 #include "main/colormac.h"
 #include "main/context.h"
 #include "main/enums.h"
@@ -1415,7 +1416,7 @@ _mesa_GetTexParameterfv( GLenum target, GLenum pname, GLfloat *params )
 
          if (ctx->NewState & (_NEW_BUFFERS | _NEW_FRAG_CLAMP))
             _mesa_update_state_locked(ctx);
-         if (ctx->Color._ClampFragmentColor) {
+         if (_mesa_get_clamp_fragment_color(ctx)) {
             params[0] = CLAMP(obj->Sampler.BorderColor.f[0], 0.0F, 1.0F);
             params[1] = CLAMP(obj->Sampler.BorderColor.f[1], 0.0F, 1.0F);
             params[2] = CLAMP(obj->Sampler.BorderColor.f[2], 0.0F, 1.0F);