[cairo] Cairo OpenGL ES 2.0 backend is rotting away?

[Alexandros Frantzis]

On Mon, Apr 23, 2012 at 03:39:28PM +0300, Siarhei Siamashka wrote:
> Hello,
> 
> Tried cairo-perf-trace benchmark using GLES2 backend (--enable-glesv2) on
> x86-64 computer with open source radeon drivers.
> 
> === after the merge of GLES2 in 4d96859ba5eb6018ae257ef6bfead228583908cf ===
> 
> [ # ]  backend                         test   min(s) median(s) stddev. count
> [  0]      egl             firefox-fishtank   10.282   10.282   0.00%    1/1
> 
> === starting with 2855ff4666922f2c38505414270d47f659b0d499 ===
> 
> [ # ]  backend                         test   min(s) median(s) stddev. count
> [  0]      egl             firefox-fishtank    0.000    0.000   -nan%    0/1
> 
> === starting with af9fbd176b145f042408ef5391eef2a51d7531f8 ===
> 
> Segmentation fault
> 
> === current git master abedc6b46ad283f896e078479174312cb87e6700 ===
> 
> cairo-perf-trace: cairo-gl-operand.c:450: _cairo_gl_operand_destroy:
> Assertion `!"reached"' failed.
> 
> -- 
> Best regards,
> Siarhei Siamashka
> 

Hi,

the patch below fixes things for me (tried it on a x86-64 with r600g).
Please try it out and check if it fixes the perf test case in your system, too.

Thanks,
Alexandros

diff --git a/src/cairo-gl-gradient.c b/src/cairo-gl-gradient.c
index ce7c0dd..08c2866 100644
--- a/src/cairo-gl-gradient.c
+++ b/src/cairo-gl-gradient.c
@@ -206,6 +206,7 @@ _cairo_gl_gradient_create (cairo_gl_context_t           *ctx,
     cairo_gl_gradient_t *gradient;
     cairo_status_t status;
     int tex_width;
+    GLint internal_format;
     void *data;
 
     if ((unsigned int) ctx->max_texture_size / 2 <= n_stops)
@@ -247,7 +248,16 @@ _cairo_gl_gradient_create (cairo_gl_context_t           *ctx,
     if (unlikely (status))
 	goto cleanup_data;
 
-    glTexImage2D (ctx->tex_target, 0, GL_RGBA, tex_width, 1, 0,
+    /* 
+     * In OpenGL ES 2.0 no format conversion is allowed i.e. 'internalFormat'
+     * must match 'format' in glTexImage2D.
+     */
+    if (_cairo_gl_get_flavor () == CAIRO_GL_FLAVOR_ES)
+	internal_format = GL_BGRA;
+    else
+	internal_format = GL_RGBA;
+
+    glTexImage2D (ctx->tex_target, 0, internal_format, tex_width, 1, 0,
 		  GL_BGRA, GL_UNSIGNED_BYTE, data);
 
     free (data);