From ba4a4eae051cd932e59e3092ef36d4f6cded0159 Mon Sep 17 00:00:00 2001
From: Chuanbo Weng <chuanbo.weng@intel.com>
Date: Tue, 2 Oct 2012 13:58:49 +0200
Subject: [PATCH] gl/msaa: Use GL_IMG_multisampled_render_to_texture when
 available

Some OpenGLES platforms support GL_IMG_multisampled_render_to_texture
instead of GL_EXT_multisampled_render_to_texture.
---
 src/cairo-gl-device.c           |  8 ++++++++
 src/cairo-gl-dispatch-private.h | 10 +++++++---
 src/cairo-gl-dispatch.c         | 26 ++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/src/cairo-gl-device.c b/src/cairo-gl-device.c
index 89d66f2a6..37c837d27 100644
--- a/src/cairo-gl-device.c
+++ b/src/cairo-gl-device.c
@@ -249,6 +249,14 @@ _cairo_gl_context_init (cairo_gl_context_t *ctx)
 	glGetIntegerv(GL_MAX_SAMPLES_EXT, &ctx->num_samples);
     }
 #endif
+
+#if CAIRO_HAS_GLESV2_SURFACE && defined(GL_MAX_SAMPLES_IMG)
+    if (ctx->has_packed_depth_stencil &&
+	_cairo_gl_has_extension ("GL_IMG_multisampled_render_to_texture")) {
+	glGetIntegerv(GL_MAX_SAMPLES_IMG, &ctx->num_samples);
+    }
+#endif
+
     ctx->supports_msaa = ctx->num_samples > 1;
     if (ctx->num_samples > MAX_MSAA_SAMPLES)
 	ctx->num_samples = MAX_MSAA_SAMPLES;
diff --git a/src/cairo-gl-dispatch-private.h b/src/cairo-gl-dispatch-private.h
index 0c5dc3900..cabf76f0d 100644
--- a/src/cairo-gl-dispatch-private.h
+++ b/src/cairo-gl-dispatch-private.h
@@ -53,7 +53,7 @@ typedef struct _cairo_gl_dispatch_entry {
 				   offsetof(cairo_gl_dispatch_t, name) }
 #define DISPATCH_ENTRY_ARB_OES(name) { { "gl"#name, "gl"#name"ARB", "gl"#name"OES" }, \
 				       offsetof(cairo_gl_dispatch_t, name) }
-#define DISPATCH_ENTRY_EXT_EXT(name) { { "gl"#name, "gl"#name"EXT", "gl"#name"EXT" }, \
+#define DISPATCH_ENTRY_EXT_IMG(name) { { "gl"#name, "gl"#name"EXT", "gl"#name"IMG" }, \
 				       offsetof(cairo_gl_dispatch_t, name) }
 #define DISPATCH_ENTRY_CUSTOM(name, name2) { { "gl"#name, "gl"#name2, "gl"#name }, \
 			                     offsetof(cairo_gl_dispatch_t, name)}
@@ -117,8 +117,12 @@ cairo_private cairo_gl_dispatch_entry_t dispatch_fbo_entries[] = {
     DISPATCH_ENTRY_EXT (FramebufferRenderbuffer),
     DISPATCH_ENTRY_EXT (DeleteRenderbuffers),
     DISPATCH_ENTRY_EXT (BlitFramebuffer),
-    DISPATCH_ENTRY_EXT_EXT (RenderbufferStorageMultisample),
-    DISPATCH_ENTRY_EXT_EXT (FramebufferTexture2DMultisample),
+    DISPATCH_ENTRY_LAST
+};
+
+cairo_private cairo_gl_dispatch_entry_t dispatch_multisampling_entries[] = {
+    DISPATCH_ENTRY_EXT_IMG (RenderbufferStorageMultisample),
+    DISPATCH_ENTRY_EXT_IMG (FramebufferTexture2DMultisample),
     DISPATCH_ENTRY_LAST
 };
 
diff --git a/src/cairo-gl-dispatch.c b/src/cairo-gl-dispatch.c
index 5bffdddad..76c3115ba 100644
--- a/src/cairo-gl-dispatch.c
+++ b/src/cairo-gl-dispatch.c
@@ -205,6 +205,27 @@ _cairo_gl_dispatch_init_fbo (cairo_gl_dispatch_t *dispatch,
     return CAIRO_STATUS_SUCCESS;
 }
 
+static cairo_status_t
+_cairo_gl_dispatch_init_multisampling (cairo_gl_dispatch_t *dispatch,
+				       cairo_gl_get_proc_addr_func_t get_proc_addr,
+				       int gl_version,
+				       cairo_gl_flavor_t gl_flavor)
+{
+    /* For the multisampling table, there are two GLES versions of the
+     * extension, so we put one in the EXT slot and one in the real ES slot.*/
+    cairo_gl_dispatch_name_t dispatch_name = CAIRO_GL_DISPATCH_NAME_CORE;
+    if (gl_flavor == CAIRO_GL_FLAVOR_ES) {
+	if (_cairo_gl_has_extension ("GL_EXT_multisampled_render_to_texture"))
+	    dispatch_name = CAIRO_GL_DISPATCH_NAME_EXT;
+	else if (_cairo_gl_has_extension ("GL_IMG_multisampled_render_to_texture"))
+	    dispatch_name = CAIRO_GL_DISPATCH_NAME_ES;
+    }
+    _cairo_gl_dispatch_init_entries (dispatch, get_proc_addr,
+				     dispatch_multisampling_entries,
+				     dispatch_name);
+    return CAIRO_STATUS_SUCCESS;
+}
+
 cairo_status_t
 _cairo_gl_dispatch_init (cairo_gl_dispatch_t *dispatch,
 			 cairo_gl_get_proc_addr_func_t get_proc_addr)
@@ -231,5 +252,10 @@ _cairo_gl_dispatch_init (cairo_gl_dispatch_t *dispatch,
     if (status != CAIRO_STATUS_SUCCESS)
 	return status;
 
+    status = _cairo_gl_dispatch_init_multisampling (dispatch, get_proc_addr,
+						    gl_version, gl_flavor);
+    if (status != CAIRO_STATUS_SUCCESS)
+	return status;
+
     return CAIRO_STATUS_SUCCESS;
 }