st/mesa: simplify and improve CopyTexSubImage

It has become a bit messy.

Changes:

- finally correct checking for transfer ops depending on the base format

- making sure the base internal format and the texture format match
  (we were ignoring it, but it's important for correctness)

- the way-too-strict rule that both src and dst base formats must be the same
  was dropped; ensuring the simpler and more permissive rule mentioned above
  is enough

- stop using util_blit_pixels; pipe->blit is flexible enough, and now that we
  have RGBX and red-alpha formats, pipe->blit can be used for more cases

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

2 files changed, 25 insertions, 16 deletions

diff --git a/src/mesa/main/texstore.c b/src/mesa/main/texstore.c
index 77222d6dfb6..0e13d8903f9 100644
--- a/src/mesa/main/texstore.c
+++ b/src/mesa/main/texstore.c
@@ -3792,26 +3792,21 @@ _mesa_get_texstore_func(gl_format format)
 
 
 GLboolean
-_mesa_texstore_can_use_memcpy(struct gl_context *ctx,
-                              GLenum baseInternalFormat, gl_format dstFormat,
-                              GLenum srcFormat, GLenum srcType,
-                              const struct gl_pixelstore_attrib *srcPacking)
+_mesa_texstore_needs_transfer_ops(struct gl_context *ctx,
+                                  GLenum baseInternalFormat,
+                                  gl_format dstFormat)
 {
    GLenum dstType;
 
-   /* There are different restrictions depending on the base format... */
+   /* There are different rules depending on the base format. */
    switch (baseInternalFormat) {
    case GL_DEPTH_COMPONENT:
    case GL_DEPTH_STENCIL:
-      /* Depth scale and bias are not allowed. */
-      if (ctx->Pixel.DepthScale != 1.0f ||
-          ctx->Pixel.DepthBias != 0.0f) {
-        return GL_FALSE;
-      }
-      break;
+      return ctx->Pixel.DepthScale != 1.0f ||
+             ctx->Pixel.DepthBias != 0.0f;
 
    case GL_STENCIL_INDEX:
-      break;
+      return GL_FALSE;
 
    default:
       /* Color formats.
@@ -3820,10 +3815,20 @@ _mesa_texstore_can_use_memcpy(struct gl_context *ctx,
        */
       dstType = _mesa_get_format_datatype(dstFormat);
 
-      if (dstType != GL_INT && dstType != GL_UNSIGNED_INT &&
-          ctx->_ImageTransferState) {
-         return GL_FALSE;
-      }
+      return dstType != GL_INT && dstType != GL_UNSIGNED_INT &&
+             ctx->_ImageTransferState;
+   }
+}
+
+
+GLboolean
+_mesa_texstore_can_use_memcpy(struct gl_context *ctx,
+                              GLenum baseInternalFormat, gl_format dstFormat,
+                              GLenum srcFormat, GLenum srcType,
+                              const struct gl_pixelstore_attrib *srcPacking)
+{
+   if (_mesa_texstore_needs_transfer_ops(ctx, baseInternalFormat, dstFormat)) {
+      return GL_FALSE;
    }
 
    /* The base internal format and the base Mesa format must match. */
diff --git a/src/mesa/main/texstore.h b/src/mesa/main/texstore.h
index 107f2130015..75f24bd45ac 100644
--- a/src/mesa/main/texstore.h
+++ b/src/mesa/main/texstore.h
@@ -69,6 +69,10 @@
 extern GLboolean
 _mesa_texstore(TEXSTORE_PARAMS);
 
+extern GLboolean
+_mesa_texstore_needs_transfer_ops(struct gl_context *ctx,
+                                  GLenum baseInternalFormat,
+                                  gl_format dstFormat);
 
 extern GLboolean
 _mesa_texstore_can_use_memcpy(struct gl_context *ctx,