This always looks crazy when I stumble across it, until I remember
what the hardware is doing. Describing it ought to short-circuit
that process next time :)
Signed-off-by: Chris Forbes <chr...@ijw.co.nz>
---
src/mesa/drivers/dri/i965/intel_state.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/intel_state.c
b/src/mesa/drivers/dri/i965/intel_state.c
index bfc35d8..1597db6 100644
--- a/src/mesa/drivers/dri/i965/intel_state.c
+++ b/src/mesa/drivers/dri/i965/intel_state.c
@@ -40,6 +40,17 @@
int
intel_translate_shadow_compare_func(GLenum func)
{
+ /* GL specifies the result of shadow comparisons as:
+ * 1 if ref <op> texel,
+ * 0 otherwise.
+ *
+ * The hardware does:
+ * 0 if texel <op> ref,
+ * 1 otherwise.
+ *
+ * So, these look a bit strange because there's both a negation
+ * and swapping of the arguments involved.
+ */
switch (func) {
case GL_NEVER:
return BRW_COMPAREFUNCTION_ALWAYS;
@@ -50,11 +61,11 @@ intel_translate_shadow_compare_func(GLenum func)
case GL_GREATER:
return BRW_COMPAREFUNCTION_GEQUAL;
case GL_GEQUAL:
- return BRW_COMPAREFUNCTION_GREATER;
+ return BRW_COMPAREFUNCTION_GREATER;
case GL_NOTEQUAL:
- return BRW_COMPAREFUNCTION_EQUAL;
+ return BRW_COMPAREFUNCTION_EQUAL;
case GL_EQUAL:
- return BRW_COMPAREFUNCTION_NOTEQUAL;
+ return BRW_COMPAREFUNCTION_NOTEQUAL;
case GL_ALWAYS:
return BRW_COMPAREFUNCTION_NEVER;
}
--
1.9.2
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