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authorKenneth Graunke <[email protected]>2014-03-21 15:58:02 -0700
committerKenneth Graunke <[email protected]>2014-03-24 14:45:03 -0700
commit630bf288de09e0fcf9734b297042cb751ec38376 (patch)
tree522c5bcbf5b7264a67b42aa0af92911294eab13c /src/mesa
parent92234b1b2aaf6ba68e786498806cefd4bd99dabc (diff)
mesa: Skip clearing color buffers when color writes are disabled.
WebGL Aquarium in Chrome 24 actually hits this. v2: Move to core Mesa (wisely suggested by Ian); only consider components which actually exist. v3: Use _mesa_format_has_color_component to determine whether components actually exist, fixing alpha format handling. v4: Add a comment, as requested by Brian. No actual code changes. Signed-off-by: Kenneth Graunke <[email protected]> Reviewed-by: Brian Paul <[email protected]> Reviewed-by: Eric Anholt <[email protected]> Reviewed-by: Ian Romanick <[email protected]> Tested-by: Dylan Baker <[email protected]>
Diffstat (limited to 'src/mesa')
-rw-r--r--src/mesa/main/clear.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/src/mesa/main/clear.c b/src/mesa/main/clear.c
index 077c5fca3b7..9df1f5e098c 100644
--- a/src/mesa/main/clear.c
+++ b/src/mesa/main/clear.c
@@ -107,6 +107,31 @@ _mesa_ClearColorIuiEXT(GLuint r, GLuint g, GLuint b, GLuint a)
/**
+ * Returns true if color writes are enabled for the given color attachment.
+ *
+ * Beyond checking ColorMask, this uses _mesa_format_has_color_component to
+ * ignore components that don't actually exist in the format (such as X in
+ * XRGB).
+ */
+static bool
+color_buffer_writes_enabled(const struct gl_context *ctx, unsigned idx)
+{
+ struct gl_renderbuffer *rb = ctx->DrawBuffer->_ColorDrawBuffers[idx];
+ GLuint c;
+ GLubyte colorMask = 0;
+
+ if (rb) {
+ for (c = 0; c < 4; c++) {
+ if (_mesa_format_has_color_component(rb->Format, c))
+ colorMask |= ctx->Color.ColorMask[idx][c];
+ }
+ }
+
+ return colorMask != 0;
+}
+
+
+/**
* Clear buffers.
*
* \param mask bit-mask indicating the buffers to be cleared.
@@ -181,7 +206,7 @@ _mesa_Clear( GLbitfield mask )
for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
GLint buf = ctx->DrawBuffer->_ColorDrawBufferIndexes[i];
- if (buf >= 0) {
+ if (buf >= 0 && color_buffer_writes_enabled(ctx, i)) {
bufferMask |= 1 << buf;
}
}