[cogl] Add a test for pipelines with sparse layer indices

[Neil Roberts <nroberts src gnome org>]

commit bf7f1e358d2dc90db984758652a88b8947eaf698
Author: Neil Roberts <neil linux intel com>
Date:   Thu Feb 9 20:36:14 2012 +0000

    Add a test for pipelines with sparse layer indices
    
    There are currently quite a few places in Cogl where we muddle the
    layer index and the texture unit number. The theory is that these two
    numbers shouldn't be related and it should be possible to pick large
    layer numbers with gaps.
    
    This patch adds a test case to check that we can reference a large
    layer number from a texture combine string by creating a pipeline with
    only three layers but that have very large layer indices. This doesn't
    currently work because Cogl interprets the numbers in the combine
    strings to be the unit indices and not the layer indices. The
    documentation however calls these numbers layer numbers so presumably
    it is not meant to work that way.
    
    There are probably many other bugs related to this that the test case
    doesn't pick up so it would be good to add some more tests here, for
    example to test that you can bind an attribute to the texture
    coordinates for a large layer index.
    
    Reviewed-by: Robert Bragg <robert linux intel com>

 tests/conform/Makefile.am            |    1 +
 tests/conform/test-conform-main.c    |    2 +
 tests/conform/test-sparse-pipeline.c |   89 ++++++++++++++++++++++++++++++++++
 3 files changed, 92 insertions(+), 0 deletions(-)
---
diff --git a/tests/conform/Makefile.am b/tests/conform/Makefile.am
index 63208b0..6b2d1dd 100644
--- a/tests/conform/Makefile.am
+++ b/tests/conform/Makefile.am
@@ -47,6 +47,7 @@ test_sources = \
 	test-offscreen.c \
 	test-primitive.c \
 	test-texture-3d.c \
+	test-sparse-pipeline.c \
 	$(NULL)
 
 test_conformance_SOURCES = $(common_sources) $(test_sources)
diff --git a/tests/conform/test-conform-main.c b/tests/conform/test-conform-main.c
index f75f3ea..a732be6 100644
--- a/tests/conform/test-conform-main.c
+++ b/tests/conform/test-conform-main.c
@@ -142,6 +142,8 @@ main (int argc, char **argv)
   ADD_TEST ("/cogl", test_cogl_color_mask);
   ADD_TEST ("/cogl", test_cogl_backface_culling);
 
+  ADD_TEST ("/cogl/pipeline", test_cogl_sparse_pipeline);
+
   UNPORTED_TEST ("/cogl/texture", test_cogl_npot_texture);
   UNPORTED_TEST ("/cogl/texture", test_cogl_multitexture);
   UNPORTED_TEST ("/cogl/texture", test_cogl_texture_mipmaps);
diff --git a/tests/conform/test-sparse-pipeline.c b/tests/conform/test-sparse-pipeline.c
new file mode 100644
index 0000000..433c0ba
--- /dev/null
+++ b/tests/conform/test-sparse-pipeline.c
@@ -0,0 +1,89 @@
+#include <cogl/cogl2-experimental.h>
+#include <string.h>
+
+#include "test-utils.h"
+
+typedef struct _TestState
+{
+  CoglContext *context;
+  int fb_width;
+  int fb_height;
+  CoglFramebuffer *fb;
+} TestState;
+
+static CoglTexture *
+create_color_texture (CoglContext *context,
+                      guint32 color)
+{
+  CoglTexture2D *tex_2d;
+
+  color = GUINT32_TO_BE (color);
+
+  tex_2d = cogl_texture_2d_new_from_data (context,
+                                          1, 1, /* width/height */
+                                          COGL_PIXEL_FORMAT_RGBA_8888_PRE,
+                                          COGL_PIXEL_FORMAT_RGBA_8888_PRE,
+                                          4, /* rowstride */
+                                          (guint8 *) &color,
+                                          NULL);
+
+  return COGL_TEXTURE (tex_2d);
+}
+
+static void
+test_sparse_layer_combine (TestState *state)
+{
+  CoglPipeline *pipeline;
+  CoglTexture *tex1, *tex2;
+
+  cogl_framebuffer_clear4f (state->fb, COGL_BUFFER_BIT_COLOR, 0, 0, 0, 1);
+
+  /* This tests that the TEXTURE_* numbers used in the layer combine
+     string refer to the layer number rather than the unit numbers by
+     creating a pipeline with very large layer numbers. This should
+     end up being mapped to much smaller unit numbers */
+
+  tex1 = create_color_texture (state->context, 0xff0000ff);
+  tex2 = create_color_texture (state->context, 0x00ff00ff);
+
+  pipeline = cogl_pipeline_new ();
+
+  cogl_pipeline_set_layer_texture (pipeline, 50, tex1);
+  cogl_pipeline_set_layer_texture (pipeline, 100, tex2);
+  cogl_pipeline_set_layer_combine (pipeline, 200,
+                                   "RGBA = ADD(TEXTURE_50, TEXTURE_100)",
+                                   NULL);
+
+  cogl_push_source (pipeline);
+  cogl_rectangle (-1, -1, 1, 1);
+  cogl_pop_source ();
+
+  test_utils_check_pixel (2, 2, 0xffff00ff);
+
+  cogl_object_unref (pipeline);
+  cogl_object_unref (tex1);
+  cogl_object_unref (tex2);
+}
+
+void
+test_cogl_sparse_pipeline (TestUtilsGTestFixture *fixture,
+                           void *data)
+{
+  TestUtilsSharedState *shared_state = data;
+  TestState state;
+
+  state.context = shared_state->ctx;
+  state.fb_width = cogl_framebuffer_get_width (shared_state->fb);
+  state.fb_height = cogl_framebuffer_get_height (shared_state->fb);
+  state.fb = shared_state->fb;
+
+  test_sparse_layer_combine (&state);
+
+  /* FIXME: This should have a lot more tests, for example testing
+     whether using an attribute with sparse texture coordinates will
+     work */
+
+  if (g_test_verbose ())
+    g_print ("OK\n");
+}
+