gallium: do a proper implementation of GL_OES_read_format

Examine the currently bound color buffer's format to see if there's a good
format/type match.

1 files changed, 97 insertions, 0 deletions

diff --git a/src/mesa/state_tracker/st_cb_get.c b/src/mesa/state_tracker/st_cb_get.c
new file mode 100644
index 00000000000..e7d7f03bc9b
--- /dev/null
+++ b/src/mesa/state_tracker/st_cb_get.c
@@ -0,0 +1,97 @@
+/**************************************************************************
+ * 
+ * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
+ * All Rights Reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ **************************************************************************/
+
+
+/**
+ * glGet functions
+ *
+ * \author Brian Paul
+ */
+
+#include "main/imports.h"
+#include "main/context.h"
+
+#include "pipe/p_defines.h"
+
+#include "st_cb_fbo.h"
+#include "st_cb_get.h"
+
+
+
+/**
+ * Examine the current color read buffer format to determine
+ * which GL pixel format/type combo is the best match.
+ */
+static void
+get_preferred_read_format_type(GLcontext *ctx, GLint *format, GLint *type)
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct st_renderbuffer *strb = st_renderbuffer(fb->_ColorReadBuffer);
+
+   /* defaults */
+   *format = ctx->Const.ColorReadFormat;
+   *type = ctx->Const.ColorReadType;
+
+   if (strb) {
+      /* XXX could add more cases here... */
+      if (strb->format == PIPE_FORMAT_A8R8G8B8_UNORM) {
+         *format = GL_BGRA;
+         if (_mesa_little_endian())
+            *type = GL_UNSIGNED_INT_8_8_8_8_REV;
+         else
+            *type = GL_UNSIGNED_INT_8_8_8_8;
+      }
+   }
+}
+
+
+/**
+ * We only intercept the OES preferred ReadPixels format/type.
+ * Everything else goes to the default _mesa_GetIntegerv.
+ */
+static GLboolean 
+st_GetIntegerv(GLcontext *ctx, GLenum pname, GLint *params)
+{
+   GLint dummy;
+
+   switch (pname) {
+   case GL_IMPLEMENTATION_COLOR_READ_TYPE_OES:
+      get_preferred_read_format_type(ctx, &dummy, params);
+      return GL_TRUE;
+   case GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES:
+      get_preferred_read_format_type(ctx, params, &dummy);
+      return GL_TRUE;
+   default:
+      return GL_FALSE;
+   }
+}
+
+
+void st_init_get_functions(struct dd_function_table *functions)
+{
+   functions->GetIntegerv = st_GetIntegerv;
+}