Simplify ctx->_NumColorDrawBuffers, _ColorDrawBuffers and fix bug 13835.

These fields are no longer indexed by shader output.  Now, we just have
a simple array of renderbuffer pointers.

If the shader writes to gl_FragData[i], send those colors to the N
_ColorDrawBuffers.  Otherwise, replicate the single gl_FragColor (or
the fixed-function color) to the N _ColorDrawBuffers.

A few more changes and simplifications can follow from this...

10 files changed, 104 insertions, 148 deletions

diff --git a/src/mesa/swrast/s_accum.c b/src/mesa/swrast/s_accum.c
index 3c45dee3998..b74f794d090 100644
--- a/src/mesa/swrast/s_accum.c
+++ b/src/mesa/swrast/s_accum.c
@@ -525,8 +525,8 @@ accum_return(GLcontext *ctx, GLfloat value,
          }
 
          /* store colors */
-         for (buffer = 0; buffer < fb->_NumColorDrawBuffers[0]; buffer++) {
-            struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[0][buffer];
+         for (buffer = 0; buffer < fb->_NumColorDrawBuffers; buffer++) {
+            struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[buffer];
             if (masking) {
                _swrast_mask_rgba_span(ctx, rb, &span);
             }
diff --git a/src/mesa/swrast/s_blit.c b/src/mesa/swrast/s_blit.c
index 5aec4aad035..a2c40bd9a6b 100644
--- a/src/mesa/swrast/s_blit.c
+++ b/src/mesa/swrast/s_blit.c
@@ -135,7 +135,7 @@ blit_nearest(GLcontext *ctx,
    switch (buffer) {
    case GL_COLOR_BUFFER_BIT:
       readRb = ctx->ReadBuffer->_ColorReadBuffer;
-      drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
+      drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0];
       comps = 4;
       break;
    case GL_DEPTH_BUFFER_BIT:
@@ -319,7 +319,7 @@ blit_linear(GLcontext *ctx,
             GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1)
 {
    struct gl_renderbuffer *readRb = ctx->ReadBuffer->_ColorReadBuffer;
-   struct gl_renderbuffer *drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
+   struct gl_renderbuffer *drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0];
 
    const GLint srcWidth = ABS(srcX1 - srcX0);
    const GLint dstWidth = ABS(dstX1 - dstX0);
@@ -493,7 +493,7 @@ simple_blit(GLcontext *ctx,
    switch (buffer) {
    case GL_COLOR_BUFFER_BIT:
       readRb = ctx->ReadBuffer->_ColorReadBuffer;
-      drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
+      drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0];
       comps = 4;
       break;
    case GL_DEPTH_BUFFER_BIT:
diff --git a/src/mesa/swrast/s_buffers.c b/src/mesa/swrast/s_buffers.c
index 90a56284c51..b74c4ab1c8c 100644
--- a/src/mesa/swrast/s_buffers.c
+++ b/src/mesa/swrast/s_buffers.c
@@ -251,7 +251,7 @@ static void
 clear_color_buffers(GLcontext *ctx)
 {
    GLboolean masking;
-   GLuint i;
+   GLuint buf;
 
    if (ctx->Visual.rgbMode) {
       if (ctx->Color.ColorMask[0] && 
@@ -265,7 +265,7 @@ clear_color_buffers(GLcontext *ctx)
       }
    }
    else {
-      struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
+      struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0];
       const GLuint indexBits = (1 << rb->IndexBits) - 1;
       if ((ctx->Color.IndexMask & indexBits) == indexBits) {
          masking = GL_FALSE;
@@ -275,8 +275,8 @@ clear_color_buffers(GLcontext *ctx)
       }
    }
 
-   for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers[0]; i++) {
-      struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0][i];
+   for (buf = 0; buf < ctx->DrawBuffer->_NumColorDrawBuffers; buf++) {
+      struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[buf];
       if (ctx->Visual.rgbMode) {
          if (masking) {
             clear_rgba_buffer_with_masking(ctx, rb);
@@ -331,7 +331,7 @@ _swrast_Clear(GLcontext *ctx, GLbitfield buffers)
 
    /* do software clearing here */
    if (buffers) {
-      if (buffers & ctx->DrawBuffer->_ColorDrawBufferMask[0]) {
+      if (buffers & ctx->DrawBuffer->_NumColorDrawBuffers > 0) {
          clear_color_buffers(ctx);
       }
       if (buffers & BUFFER_BIT_DEPTH) {
diff --git a/src/mesa/swrast/s_context.c b/src/mesa/swrast/s_context.c
index 314931d4676..8e6b28bb4c6 100644
--- a/src/mesa/swrast/s_context.c
+++ b/src/mesa/swrast/s_context.c
@@ -87,7 +87,7 @@ _swrast_update_rasterflags( GLcontext *ctx )
     * MULTI_DRAW_BIT flag.  Also set it if we're drawing to no
     * buffers or the RGBA or CI mask disables all writes.
     */
-   if (ctx->DrawBuffer->_NumColorDrawBuffers[0] != 1) {
+   if (ctx->DrawBuffer->_NumColorDrawBuffers != 1) {
       /* more than one color buffer designated for writing (or zero buffers) */
       rasterMask |= MULTI_DRAW_BIT;
    }
@@ -596,44 +596,6 @@ _swrast_update_active_attribs(GLcontext *ctx)
 }
 
 
-/**
- * Update the swrast->_ColorOutputsMask which indicates which color
- * renderbuffers (aka rendertargets) are being written to by the current
- * fragment program.
- * We also take glDrawBuffers() into account to skip outputs that are
- * set to GL_NONE.
- */
-static void
-_swrast_update_color_outputs(GLcontext *ctx)
-{
-   SWcontext *swrast = SWRAST_CONTEXT(ctx);
-   const struct gl_framebuffer *fb = ctx->DrawBuffer;
-
-   swrast->_ColorOutputsMask = 0;
-   swrast->_NumColorOutputs = 0;
-
-   if (ctx->FragmentProgram._Current) {
-      const GLbitfield outputsWritten
-         = ctx->FragmentProgram._Current->Base.OutputsWritten;
-      GLuint output;
-      for (output = 0; output < ctx->Const.MaxDrawBuffers; output++) {
-         if ((outputsWritten & (1 << (FRAG_RESULT_DATA0 + output)))
-             && (fb->_NumColorDrawBuffers[output] > 0)) {
-            swrast->_ColorOutputsMask |= (1 << output);
-            swrast->_NumColorOutputs = output + 1;
-         }
-      }
-   }
-   if (swrast->_ColorOutputsMask == 0x0) {
-      /* no fragment program, or frag prog didn't write to gl_FragData[] */
-      if (fb->_NumColorDrawBuffers[0] > 0) {
-         swrast->_ColorOutputsMask = 0x1;
-         swrast->_NumColorOutputs = 1;
-      }
-   }
-}
-
-
 void
 _swrast_validate_derived( GLcontext *ctx )
 {
@@ -683,9 +645,6 @@ _swrast_validate_derived( GLcontext *ctx )
                               _NEW_TEXTURE))
          _swrast_update_active_attribs(ctx);
 
-      if (swrast->NewState & (_NEW_PROGRAM | _NEW_BUFFERS))
-         _swrast_update_color_outputs(ctx);
-
       swrast->NewState = 0;
       swrast->StateChanges = 0;
       swrast->InvalidateState = _swrast_invalidate_state;
diff --git a/src/mesa/swrast/s_context.h b/src/mesa/swrast/s_context.h
index aebc80c2080..3dcc3ed16e2 100644
--- a/src/mesa/swrast/s_context.h
+++ b/src/mesa/swrast/s_context.h
@@ -136,10 +136,6 @@ typedef struct
    GLboolean _DeferredTexture;
    GLenum _FogMode;  /* either GL_FOG_MODE or fragment program's fog mode */
 
-   /** Multiple render targets */
-   GLbitfield _ColorOutputsMask;
-   GLuint _NumColorOutputs;
-
    /** List/array of the fragment attributes to interpolate */
    GLuint _ActiveAttribs[FRAG_ATTRIB_MAX];
    /** Same info, but as a bitmask */
diff --git a/src/mesa/swrast/s_copypix.c b/src/mesa/swrast/s_copypix.c
index 218a3b5590b..3962721a61c 100644
--- a/src/mesa/swrast/s_copypix.c
+++ b/src/mesa/swrast/s_copypix.c
@@ -830,10 +830,10 @@ fast_copy_pixels(GLcontext *ctx,
    }
 
    if (type == GL_COLOR) {
-      if (dstFb->_NumColorDrawBuffers[0] != 1)
+      if (dstFb->_NumColorDrawBuffers != 1)
          return GL_FALSE;
       srcRb = srcFb->_ColorReadBuffer;
-      dstRb = dstFb->_ColorDrawBuffers[0][0];
+      dstRb = dstFb->_ColorDrawBuffers[0];
    }
    else if (type == GL_STENCIL) {
       srcRb = srcFb->_StencilBuffer;
diff --git a/src/mesa/swrast/s_drawpix.c b/src/mesa/swrast/s_drawpix.c
index 969787381c2..7bab14f200e 100644
--- a/src/mesa/swrast/s_drawpix.c
+++ b/src/mesa/swrast/s_drawpix.c
@@ -53,7 +53,7 @@ fast_draw_rgba_pixels(GLcontext *ctx, GLint x, GLint y,
                       const GLvoid *pixels)
 {
    const GLint imgX = x, imgY = y;
-   struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
+   struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0];
    const GLenum rbType = rb->DataType;
    SWcontext *swrast = SWRAST_CONTEXT(ctx);
    SWspan span;
@@ -608,8 +608,8 @@ draw_rgba_pixels( GLcontext *ctx, GLint x, GLint y,
                        IMAGE_POST_CONVOLUTION_SCALE_BIAS);
    }
 
-   if (ctx->DrawBuffer->_NumColorDrawBuffers[0] > 0 &&
-       ctx->DrawBuffer->_ColorDrawBuffers[0][0]->DataType != GL_FLOAT &&
+   if (ctx->DrawBuffer->_NumColorDrawBuffers > 0 &&
+       ctx->DrawBuffer->_ColorDrawBuffers[0]->DataType != GL_FLOAT &&
        ctx->Color.ClampFragmentColor != GL_FALSE) {
       /* need to clamp colors before applying fragment ops */
       transferOps |= IMAGE_CLAMP_BIT;
diff --git a/src/mesa/swrast/s_fragprog.c b/src/mesa/swrast/s_fragprog.c
index 76c79eb0d81..2dfc033d501 100644
--- a/src/mesa/swrast/s_fragprog.c
+++ b/src/mesa/swrast/s_fragprog.c
@@ -167,11 +167,11 @@ run_program(GLcontext *ctx, SWspan *span, GLuint start, GLuint end)
                 * Note that colors beyond 0 and 1 will overwrite other
                 * attributes, such as FOGC, TEX0, TEX1, etc.  That's OK.
                 */
-               GLuint output;
-               for (output = 0; output < swrast->_NumColorOutputs; output++) {
-                  if (outputsWritten & (1 << (FRAG_RESULT_DATA0 + output))) {
-                     COPY_4V(span->array->attribs[FRAG_ATTRIB_COL0+output][i],
-                             machine->Outputs[FRAG_RESULT_DATA0 + output]);
+               GLuint buf;
+               for (buf = 0; buf < ctx->DrawBuffer->_NumColorDrawBuffers; buf++) {
+                  if (outputsWritten & (1 << (FRAG_RESULT_DATA0 + buf))) {
+                     COPY_4V(span->array->attribs[FRAG_ATTRIB_COL0 + buf][i],
+                             machine->Outputs[FRAG_RESULT_DATA0 + buf]);
                   }
                }
             }
diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c
index 000e192a4a5..d4045792790 100644
--- a/src/mesa/swrast/s_span.c
+++ b/src/mesa/swrast/s_span.c
@@ -792,6 +792,7 @@ _swrast_write_index_span( GLcontext *ctx, SWspan *span)
    const SWcontext *swrast = SWRAST_CONTEXT(ctx);
    const GLbitfield origInterpMask = span->interpMask;
    const GLbitfield origArrayMask = span->arrayMask;
+   struct gl_framebuffer *fb = ctx->DrawBuffer;
 
    ASSERT(span->end <= MAX_WIDTH);
    ASSERT(span->primitive == GL_POINT  ||  span->primitive == GL_LINE ||
@@ -818,7 +819,7 @@ _swrast_write_index_span( GLcontext *ctx, SWspan *span)
    }
 
    /* Depth bounds test */
-   if (ctx->Depth.BoundsTest && ctx->DrawBuffer->Visual.depthBits > 0) {
+   if (ctx->Depth.BoundsTest && fb->Visual.depthBits > 0) {
       if (!_swrast_depth_bounds_test(ctx, span)) {
          return;
       }
@@ -830,10 +831,10 @@ _swrast_write_index_span( GLcontext *ctx, SWspan *span)
       GLuint i;
       for (i = 0; i < span->end; i++) {
          if (span->array->mask[i]) {
-            assert(span->array->x[i] >= ctx->DrawBuffer->_Xmin);
-            assert(span->array->x[i] < ctx->DrawBuffer->_Xmax);
-            assert(span->array->y[i] >= ctx->DrawBuffer->_Ymin);
-            assert(span->array->y[i] < ctx->DrawBuffer->_Ymax);
+            assert(span->array->x[i] >= fb->_Xmin);
+            assert(span->array->x[i] < fb->_Xmax);
+            assert(span->array->y[i] >= fb->_Ymin);
+            assert(span->array->y[i] < fb->_Ymax);
          }
       }
    }
@@ -912,22 +913,21 @@ _swrast_write_index_span( GLcontext *ctx, SWspan *span)
     * Write to renderbuffers
     */
    {
-      struct gl_framebuffer *fb = ctx->DrawBuffer;
-      const GLuint output = 0; /* only frag progs can write to other outputs */
-      const GLuint numDrawBuffers = fb->_NumColorDrawBuffers[output];
-      GLuint indexSave[MAX_WIDTH];
+      const GLuint numBuffers = fb->_NumColorDrawBuffers;
       GLuint buf;
 
-      if (numDrawBuffers > 1) {
-         /* save indexes for second, third renderbuffer writes */
-         _mesa_memcpy(indexSave, span->array->index,
-                      span->end * sizeof(indexSave[0]));
-      }
+      for (buf = 0; buf < numBuffers; buf++) {
+         struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[buf];
+         GLuint indexSave[MAX_WIDTH];
 
-      for (buf = 0; buf < fb->_NumColorDrawBuffers[output]; buf++) {
-         struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[output][buf];
          ASSERT(rb->_BaseFormat == GL_COLOR_INDEX);
 
+         if (numBuffers > 1) {
+            /* save indexes for second, third renderbuffer writes */
+            _mesa_memcpy(indexSave, span->array->index,
+                         span->end * sizeof(indexSave[0]));
+         }
+
          if (ctx->Color.IndexLogicOpEnabled) {
             _swrast_logicop_ci_span(ctx, rb, span);
          }
@@ -1002,7 +1002,7 @@ _swrast_write_index_span( GLcontext *ctx, SWspan *span)
             }
          }
 
-         if (buf + 1 < numDrawBuffers) {
+         if (buf + 1 < numBuffers) {
             /* restore original span values */
             _mesa_memcpy(span->array->index, indexSave,
                          span->end * sizeof(indexSave[0]));
@@ -1119,7 +1119,7 @@ clamp_colors(SWspan *span)
 
 /**
  * Convert the span's color arrays to the given type.
- * The only way 'output' can be greater than one is when we have a fragment
+ * The only way 'output' can be greater than zero is when we have a fragment
  * program that writes to gl_FragData[1] or higher.
  * \param output  which fragment program color output is being processed
  */
@@ -1249,7 +1249,6 @@ _swrast_write_rgba_span( GLcontext *ctx, SWspan *span)
                              || ctx->ATIFragmentShader._Enabled);
    const GLboolean shaderOrTexture = shader || ctx->Texture._EnabledUnits;
    struct gl_framebuffer *fb = ctx->DrawBuffer;
-   GLuint output;
 
    /*
    printf("%s()  interp 0x%x  array 0x%x\n", __FUNCTION__,
@@ -1399,67 +1398,69 @@ _swrast_write_rgba_span( GLcontext *ctx, SWspan *span)
    /*
     * Write to renderbuffers
     */
-   /* Loop over color outputs (GL_ARB_draw_buffers) written by frag prog */
-   for (output = 0; output < swrast->_NumColorOutputs; output++) {
-      if (swrast->_ColorOutputsMask & (1 << output)) {
-        const GLuint numDrawBuffers = fb->_NumColorDrawBuffers[output];
-        GLchan rgbaSave[MAX_WIDTH][4];
-        GLuint buf;
-
-        ASSERT(numDrawBuffers > 0);
-
-        if (fb->_ColorDrawBuffers[output][0]->DataType
-            != span->array->ChanType || output > 0) {
-           convert_color_type(span,
-                              fb->_ColorDrawBuffers[output][0]->DataType,
-                              output);
-        }
-
-        if (numDrawBuffers > 1) {
-           /* save colors for second, third renderbuffer writes */
-           _mesa_memcpy(rgbaSave, span->array->rgba,
-                        4 * span->end * sizeof(GLchan));
-        }
-
-        /* Loop over renderbuffers (i.e. GL_FRONT_AND_BACK) */
-        for (buf = 0; buf < numDrawBuffers; buf++) {
-           struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[output][buf];
-           ASSERT(rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB);
-
-           if (ctx->Color._LogicOpEnabled) {
-              _swrast_logicop_rgba_span(ctx, rb, span);
-           }
-           else if (ctx->Color.BlendEnabled) {
-              _swrast_blend_span(ctx, rb, span);
-           }
-
-           if (colorMask != 0xffffffff) {
-              _swrast_mask_rgba_span(ctx, rb, span);
-           }
-
-           if (span->arrayMask & SPAN_XY) {
-              /* array of pixel coords */
-              ASSERT(rb->PutValues);
-              rb->PutValues(ctx, rb, span->end,
-                            span->array->x, span->array->y,
-                            span->array->rgba, span->array->mask);
-           }
-           else {
-              /* horizontal run of pixels */
-              ASSERT(rb->PutRow);
-              rb->PutRow(ctx, rb, span->end, span->x, span->y,
-                         span->array->rgba,
-                         span->writeAll ? NULL: span->array->mask);
-           }
-
-           if (buf + 1 < numDrawBuffers) {
-              /* restore original span values */
-              _mesa_memcpy(span->array->rgba, rgbaSave,
-                           4 * span->end * sizeof(GLchan));
-           }
-        } /* for buf */
-      } /* if output is written to */
-   } /* for output */
+   {
+      const struct gl_fragment_program *fp = ctx->FragmentProgram._Current;
+      const GLboolean multiFragOutputs
+         = fp && fp->Base.InputsRead >= (1 << FRAG_RESULT_DATA0);
+      const GLuint numBuffers = fb->_NumColorDrawBuffers;
+      GLuint buf;
+
+      for (buf = 0; buf < numBuffers; buf++) {
+         struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[buf];
+
+         /* color[fragOutput] will be written to buffer[buf] */
+
+         if (rb) {
+            GLchan rgbaSave[MAX_WIDTH][4];
+            const GLuint fragOutput = multiFragOutputs ? buf : 0;
+
+            if (rb->DataType != span->array->ChanType || fragOutput > 0) {
+               convert_color_type(span, rb->DataType, fragOutput);
+            }
+
+            if (!multiFragOutputs && numBuffers > 1) {
+               /* save colors for second, third renderbuffer writes */
+               _mesa_memcpy(rgbaSave, span->array->rgba,
+                            4 * span->end * sizeof(GLchan));
+            }
+
+            ASSERT(rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB);
+
+            if (ctx->Color._LogicOpEnabled) {
+               _swrast_logicop_rgba_span(ctx, rb, span);
+            }
+            else if (ctx->Color.BlendEnabled) {
+               _swrast_blend_span(ctx, rb, span);
+            }
+
+            if (colorMask != 0xffffffff) {
+               _swrast_mask_rgba_span(ctx, rb, span);
+            }
+
+            if (span->arrayMask & SPAN_XY) {
+               /* array of pixel coords */
+               ASSERT(rb->PutValues);
+               rb->PutValues(ctx, rb, span->end,
+                             span->array->x, span->array->y,
+                             span->array->rgba, span->array->mask);
+            }
+            else {
+               /* horizontal run of pixels */
+               ASSERT(rb->PutRow);
+               rb->PutRow(ctx, rb, span->end, span->x, span->y,
+                          span->array->rgba,
+                          span->writeAll ? NULL: span->array->mask);
+            }
+
+            if (!multiFragOutputs && numBuffers > 1) {
+               /* restore original span values */
+               _mesa_memcpy(span->array->rgba, rgbaSave,
+                            4 * span->end * sizeof(GLchan));
+            }
+
+         } /* if rb */
+      } /* for buf */
+   }
 
 end:
    /* restore these values before returning */
diff --git a/src/mesa/swrast/s_triangle.c b/src/mesa/swrast/s_triangle.c
index 938cdefa561..5036020b7c4 100644
--- a/src/mesa/swrast/s_triangle.c
+++ b/src/mesa/swrast/s_triangle.c
@@ -130,7 +130,7 @@ _swrast_culltriangle( GLcontext *ctx,
 #define T_SCALE theight
 
 #define SETUP_CODE							\
-   struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];\
+   struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0];\
    struct gl_texture_object *obj = ctx->Texture.Unit[0].Current2D;	\
    const GLint b = obj->BaseLevel;					\
    const GLfloat twidth = (GLfloat) obj->Image[0][b]->Width;		\
@@ -182,7 +182,7 @@ _swrast_culltriangle( GLcontext *ctx,
 #define T_SCALE theight
 
 #define SETUP_CODE							\
-   struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];\
+   struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[0];\
    struct gl_texture_object *obj = ctx->Texture.Unit[0].Current2D;	\
    const GLint b = obj->BaseLevel;					\
    const GLfloat twidth = (GLfloat) obj->Image[0][b]->Width;		\