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-rw-r--r--src/mesa/main/multisample.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/src/mesa/main/multisample.c b/src/mesa/main/multisample.c
index 2484946158f..8e5a969e3a8 100644
--- a/src/mesa/main/multisample.c
+++ b/src/mesa/main/multisample.c
@@ -29,6 +29,7 @@
#include "main/multisample.h"
#include "main/mtypes.h"
#include "main/fbobject.h"
+#include "main/glformats.h"
/**
@@ -112,3 +113,56 @@ _mesa_SampleMaski(GLuint index, GLbitfield mask)
FLUSH_VERTICES(ctx, _NEW_MULTISAMPLE);
ctx->Multisample.SampleMaskValue = mask;
}
+
+
+/* Helper for checking a requested sample count against the limit
+ * for a particular (target, internalFormat) pair. The limit imposed,
+ * and the error generated, both depend on which extensions are supported.
+ *
+ * Returns a GL error enum, or GL_NO_ERROR if the requested sample count is
+ * acceptable.
+ */
+GLenum
+_mesa_check_sample_count(struct gl_context *ctx, GLenum target,
+ GLenum internalFormat, GLsizei samples)
+{
+ /* If ARB_internalformat_query is supported, then treat its highest returned sample
+ * count as the absolute maximum for this format; it is allowed to exceed MAX_SAMPLES.
+ *
+ * From the ARB_internalformat_query spec:
+ *
+ * "If <samples is greater than the maximum number of samples supported
+ * for <internalformat> then the error INVALID_OPERATION is generated."
+ */
+ if (ctx->Extensions.ARB_internalformat_query) {
+ GLint buffer[16];
+ int count = ctx->Driver.QuerySamplesForFormat(ctx, target, internalFormat, buffer);
+ int limit = count ? buffer[0] : -1;
+
+ return samples > limit ? GL_INVALID_OPERATION : GL_NO_ERROR;
+ }
+
+ /* If ARB_texture_multisample is supported, we have separate limits for
+ * integer formats.
+ *
+ * From the ARB_texture_multisample spec:
+ *
+ * "If <internalformat> is a signed or unsigned integer format and
+ * <samples> is greater than the value of MAX_INTEGER_SAMPLES, then the
+ * error INVALID_OPERATION is generated"
+ */
+
+ if (ctx->Extensions.ARB_texture_multisample) {
+ if (_mesa_is_enum_format_integer(internalFormat))
+ return samples > ctx->Const.MaxIntegerSamples ? GL_INVALID_OPERATION : GL_NO_ERROR;
+ }
+
+ /* No more specific limit is available, so just use MAX_SAMPLES:
+ *
+ * On p205 of the GL3.1 spec:
+ *
+ * "... or if samples is greater than MAX_SAMPLES, then the error
+ * INVALID_VALUE is generated"
+ */
+ return samples > ctx->Const.MaxSamples ? GL_INVALID_VALUE : GL_NO_ERROR;
+}