swrast: fix multiple color buffer writing

If a fragment program wrote to more than one color buffer, the
first fragment color got replicated to all dest buffers.  This
fixes 5 piglit FBO tests, including fbo-drawbuffers-arbfp.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45348
Cc: "10.4, 10.5" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
(cherry picked from commit 89c96afe3c0acf8f2fccaf02da02945afe8ba5f3)

1 files changed, 14 insertions, 11 deletions

diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c
index caea673f2f0..321959df933 100644
--- a/src/mesa/swrast/s_span.c
+++ b/src/mesa/swrast/s_span.c
@@ -933,19 +933,19 @@ clamp_colors(SWspan *span)
  * \param output  which fragment program color output is being processed
  */
 static inline void
-convert_color_type(SWspan *span, GLenum newType, GLuint output)
+convert_color_type(SWspan *span, GLenum srcType, GLenum newType, GLuint output)
 {
    GLvoid *src, *dst;
 
-   if (output > 0 || span->array->ChanType == GL_FLOAT) {
+   if (output > 0 || srcType == GL_FLOAT) {
       src = span->array->attribs[VARYING_SLOT_COL0 + output];
       span->array->ChanType = GL_FLOAT;
    }
-   else if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+   else if (srcType == GL_UNSIGNED_BYTE) {
       src = span->array->rgba8;
    }
    else {
-      ASSERT(span->array->ChanType == GL_UNSIGNED_SHORT);
+      ASSERT(srcType == GL_UNSIGNED_SHORT);
       src = span->array->rgba16;
    }
 
@@ -979,7 +979,7 @@ shade_texture_span(struct gl_context *ctx, SWspan *span)
        ctx->ATIFragmentShader._Enabled) {
       /* programmable shading */
       if (span->primitive == GL_BITMAP && span->array->ChanType != GL_FLOAT) {
-         convert_color_type(span, GL_FLOAT, 0);
+         convert_color_type(span, span->array->ChanType, GL_FLOAT, 0);
       }
       else {
          span->array->rgba = (void *) span->array->attribs[VARYING_SLOT_COL0];
@@ -1314,6 +1314,8 @@ _swrast_write_rgba_span( struct gl_context *ctx, SWspan *span)
       const GLboolean multiFragOutputs = 
          _swrast_use_fragment_program(ctx)
          && fp->Base.OutputsWritten >= (1 << FRAG_RESULT_DATA0);
+      /* Save srcColorType because convert_color_type() can change it */
+      const GLenum srcColorType = span->array->ChanType;
       GLuint buf;
 
       for (buf = 0; buf < numBuffers; buf++) {
@@ -1325,17 +1327,18 @@ _swrast_write_rgba_span( struct gl_context *ctx, SWspan *span)
             /* re-use one of the attribute array buffers for rgbaSave */
             GLchan (*rgbaSave)[4] = (GLchan (*)[4]) span->array->attribs[0];
             struct swrast_renderbuffer *srb = swrast_renderbuffer(rb);
-            GLenum colorType = srb->ColorType;
+            const GLenum dstColorType = srb->ColorType;
 
-            assert(colorType == GL_UNSIGNED_BYTE ||
-                   colorType == GL_FLOAT);
+            assert(dstColorType == GL_UNSIGNED_BYTE ||
+                   dstColorType == GL_FLOAT);
 
             /* set span->array->rgba to colors for renderbuffer's datatype */
-            if (span->array->ChanType != colorType) {
-               convert_color_type(span, colorType, 0);
+            if (srcColorType != dstColorType) {
+               convert_color_type(span, srcColorType, dstColorType,
+                                  multiFragOutputs ? buf : 0);
             }
             else {
-               if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+               if (srcColorType == GL_UNSIGNED_BYTE) {
                   span->array->rgba = span->array->rgba8;
                }
                else {