Add a conformance test using alpha textures

This adds a conformance test with an alpha-component texture. The
texture is rendered using a pipeline with the same layer combine mode
as cogl-pango.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 05190519bad4519e66cbdb5326943c832d15a841)

tests/conform/Makefile.am

@@ -60,6 +60,7 @@ test_sources = \
 	test-alpha-test.c \
 	test-map-buffer-range.c \
 	test-npot-texture.c \
+	test-alpha-textures.c \
 	$(NULL)
 
 test_conformance_SOURCES = $(common_sources) $(test_sources)

tests/conform/test-alpha-textures.c

@@ -0,0 +1,124 @@
+#include <cogl/cogl.h>
+
+#include <string.h>
+
+#include "test-utils.h"
+
+static void
+create_pipeline (CoglTexture **tex_out,
+                 CoglPipeline **pipeline_out)
+{
+  CoglTexture2D *tex;
+  CoglPipeline *pipeline;
+  static const uint8_t tex_data[] =
+    { 0x00, 0x44, 0x88, 0xcc };
+
+  tex = cogl_texture_2d_new_from_data (test_ctx,
+                                       2, 2, /* width/height */
+                                       COGL_PIXEL_FORMAT_A_8, /* format */
+                                       COGL_PIXEL_FORMAT_ANY, /* int. format */
+                                       2, /* rowstride */
+                                       tex_data,
+                                       NULL);
+
+  pipeline = cogl_pipeline_new (test_ctx);
+
+  cogl_pipeline_set_layer_filters (pipeline,
+                                   0, /* layer */
+                                   COGL_PIPELINE_FILTER_NEAREST,
+                                   COGL_PIPELINE_FILTER_NEAREST);
+  cogl_pipeline_set_layer_wrap_mode (pipeline,
+                                     0, /* layer */
+                                     COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE);
+
+  /* This is the layer combine used by cogl-pango */
+  cogl_pipeline_set_layer_combine (pipeline,
+                                   0, /* layer */
+                                   "RGBA = MODULATE (PREVIOUS, TEXTURE[A])",
+                                   NULL);
+
+  cogl_pipeline_set_layer_texture (pipeline,
+                                   0, /* layer */
+                                   COGL_TEXTURE (tex));
+
+  *pipeline_out = pipeline;
+  *tex_out = COGL_TEXTURE (tex);
+}
+
+void
+test_alpha_textures (void)
+{
+  CoglTexture *tex1, *tex2;
+  CoglPipeline *pipeline1, *pipeline2;
+  int fb_width = cogl_framebuffer_get_width (test_fb);
+  int fb_height = cogl_framebuffer_get_height (test_fb);
+  uint8_t replacement_data[1] = { 0xff };
+
+  create_pipeline (&tex1, &pipeline1);
+
+  cogl_framebuffer_draw_rectangle (test_fb,
+                                   pipeline1,
+                                   -1.0f, 1.0f, /* x1/y1 */
+                                   1.0f, 0.0f /* x2/y2 */);
+
+  create_pipeline (&tex2, &pipeline2);
+
+  cogl_texture_set_region (tex2,
+                           0, 0, /* src_x/y */
+                           1, 1, /* dst_x/y */
+                           1, 1, /* dst_width / dst_height */
+                           1, 1, /* width / height */
+                           COGL_PIXEL_FORMAT_A_8,
+                           1, /* rowstride */
+                           replacement_data);
+
+  cogl_framebuffer_draw_rectangle (test_fb,
+                                   pipeline2,
+                                   -1.0f, 0.0f, /* x1/y1 */
+                                   1.0f, -1.0f /* x2/y2 */);
+
+  cogl_object_unref (tex1);
+  cogl_object_unref (tex2);
+  cogl_object_unref (pipeline1);
+  cogl_object_unref (pipeline2);
+
+  /* Unmodified texture */
+  test_utils_check_pixel (test_fb,
+                          fb_width / 4,
+                          fb_height / 8,
+                          0x000000ff);
+  test_utils_check_pixel (test_fb,
+                          fb_width * 3 / 4,
+                          fb_height / 8,
+                          0x444444ff);
+  test_utils_check_pixel (test_fb,
+                          fb_width / 4,
+                          fb_height * 3 / 8,
+                          0x888888ff);
+  test_utils_check_pixel (test_fb,
+                          fb_width * 3 / 4,
+                          fb_height * 3 / 8,
+                          0xccccccff);
+
+  /* Modified texture */
+  test_utils_check_pixel (test_fb,
+                          fb_width / 4,
+                          fb_height * 5 / 8,
+                          0x000000ff);
+  test_utils_check_pixel (test_fb,
+                          fb_width * 3 / 4,
+                          fb_height * 5 / 8,
+                          0x444444ff);
+  test_utils_check_pixel (test_fb,
+                          fb_width / 4,
+                          fb_height * 7 / 8,
+                          0x888888ff);
+  test_utils_check_pixel (test_fb,
+                          fb_width * 3 / 4,
+                          fb_height * 7 / 8,
+                          0xffffffff);
+
+  if (cogl_test_verbose ())
+    g_print ("OK\n");
+}
+

tests/conform/test-conform-main.c

@@ -77,6 +77,7 @@ main (int argc, char **argv)
   ADD_TEST (test_atlas_migration, 0, 0);
   ADD_TEST (test_read_texture_formats, 0, 0);
   ADD_TEST (test_write_texture_formats, 0, 0);
+  ADD_TEST (test_alpha_textures, 0, 0);
 
   UNPORTED_TEST (test_vertex_buffer_contiguous);
   UNPORTED_TEST (test_vertex_buffer_interleved);