mesa: add/update comments in _mesa_copy_buffer_subdata()

[mesa.git] / src / mesa / drivers / dri / i965 / gen6_cc.c

diff --git a/src/mesa/drivers/dri/i965/gen6_cc.c b/src/mesa/drivers/dri/i965/gen6_cc.c
index 41d13ad2bf4b1bb1ffbb6290306dae4abc42704a..916ec7d0456a90020629023a5c906a95ce102679 100644 (file)
--- a/src/mesa/drivers/dri/i965/gen6_cc.c
+++ b/src/mesa/drivers/dri/i965/gen6_cc.c
@@ -33,7 +33,7 @@
 #include "main/macros.h"
 
 static void
-prepare_blend_state(struct brw_context *brw)
+gen6_upload_blend_state(struct brw_context *brw)
 {
    struct gl_context *ctx = &brw->intel.ctx;
    struct gen6_blend_state *blend;
@@ -58,13 +58,13 @@ prepare_blend_state(struct brw_context *brw)
 
    for (b = 0; b < nr_draw_buffers; b++) {
       /* _NEW_COLOR */
-      if (ctx->Color._LogicOpEnabled) {
+      if (ctx->Color.ColorLogicOpEnabled) {
         struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[b];
         /* _NEW_BUFFERS */
         /* Floating point RTs should have no effect from LogicOp,
          * except for disabling of blending
          */
-        if (_mesa_get_format_datatype(rb->Format) != GL_FLOAT) {
+        if (rb && _mesa_get_format_datatype(rb->Format) != GL_FLOAT) {
            blend[b].blend1.logic_op_enable = 1;
            blend[b].blend1.logic_op_func =
               intel_translate_logic_op(ctx->Color.LogicOp);
@@ -99,6 +99,26 @@ prepare_blend_state(struct brw_context *brw)
                                         eqA != eqRGB);
       }
 
+      /* See section 8.1.6 "Pre-Blend Color Clamping" of the
+       * SandyBridge PRM Volume 2 Part 1 for HW requirements.
+       *
+       * We do our ARB_color_buffer_float CLAMP_FRAGMENT_COLOR
+       * clamping in the fragment shader.  For its clamping of
+       * blending, the spec says:
+       *
+       *     "RESOLVED: For fixed-point color buffers, the inputs and
+       *      the result of the blending equation are clamped.  For
+       *      floating-point color buffers, no clamping occurs."
+       *
+       * So, generally, we want clamping to the render target's range.
+       * And, good news, the hardware tables for both pre- and
+       * post-blend color clamping are either ignored, or any are
+       * allowed, or clamping is required but RT range clamping is a
+       * valid option.
+       */
+      blend[b].blend1.pre_blend_clamp_enable = 1;
+      blend[b].blend1.post_blend_clamp_enable = 1;
+      blend[b].blend1.clamp_range = BRW_RENDERTARGET_CLAMPRANGE_FORMAT;
 
       /* _NEW_COLOR */
       if (ctx->Color.AlphaEnabled) {
@@ -131,11 +151,11 @@ const struct brw_tracked_state gen6_blend_state = {
       .brw = BRW_NEW_BATCH,
       .cache = 0,
    },
-   .prepare = prepare_blend_state,
+   .emit = gen6_upload_blend_state,
 };
 
 static void
-gen6_prepare_color_calc_state(struct brw_context *brw)
+gen6_upload_color_calc_state(struct brw_context *brw)
 {
    struct gl_context *ctx = &brw->intel.ctx;
    struct gen6_color_calc_state *cc;
@@ -167,7 +187,7 @@ const struct brw_tracked_state gen6_color_calc_state = {
       .brw = BRW_NEW_BATCH,
       .cache = 0,
    },
-   .prepare = gen6_prepare_color_calc_state,
+   .emit = gen6_upload_color_calc_state,
 };
 
 static void upload_cc_state_pointers(struct brw_context *brw)