tests/cogl: Migrate just-vertex-shader

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2555>

src/tests/cogl/conform/meson.build

@@ -5,6 +5,7 @@ cogl_tests = [
   'test-depth-test',
   'test-color-hsl',
   'test-backface-culling',
+  'test-just-vertex-shader',
 ]
 
 cogl_test_conformance_includes = [

src/tests/cogl/conform/test-just-vertex-shader.c

@@ -0,0 +1,121 @@
+#include <cogl/cogl.h>
+
+#include <string.h>
+
+#include "tests/cogl-test-utils.h"
+
+typedef struct _TestState
+{
+  int paddiing;
+} TestState;
+
+static CoglTexture *
+create_dummy_texture (void)
+{
+  /* Create a dummy 1x1 green texture to replace the color from the
+     vertex shader */
+  static const uint8_t data[4] = { 0x00, 0xff, 0x00, 0xff };
+
+  return test_utils_texture_new_from_data (test_ctx,
+                                           1, 1, /* size */
+                                           TEST_UTILS_TEXTURE_NONE,
+                                           COGL_PIXEL_FORMAT_RGB_888,
+                                           4, /* rowstride */
+                                           data);
+}
+
+static void
+paint (TestState *state)
+{
+  CoglPipeline *pipeline = cogl_pipeline_new (test_ctx);
+  CoglTexture *tex;
+  CoglColor color;
+  GError *error = NULL;
+  CoglHandle shader, program;
+
+  cogl_color_init_from_4ub (&color, 0, 0, 0, 255);
+  cogl_framebuffer_clear (test_fb, COGL_BUFFER_BIT_COLOR, &color);
+
+  /* Set the primary vertex color as red */
+  cogl_color_init_from_4ub (&color, 0xff, 0x00, 0x00, 0xff);
+  cogl_pipeline_set_color (pipeline, &color);
+
+  /* Override the vertex color in the texture environment with a
+     constant green color provided by a texture */
+  tex = create_dummy_texture ();
+  cogl_pipeline_set_layer_texture (pipeline, 0, tex);
+  cogl_object_unref (tex);
+  if (!cogl_pipeline_set_layer_combine (pipeline, 0,
+                                        "RGBA=REPLACE(TEXTURE)",
+                                        &error))
+    {
+      g_warning ("Error setting layer combine: %s", error->message);
+      g_assert_not_reached ();
+    }
+
+  /* Set up a dummy vertex shader that does nothing but the usual
+     fixed function transform */
+  shader = cogl_create_shader (COGL_SHADER_TYPE_VERTEX);
+  cogl_shader_source (shader,
+                      "void\n"
+                      "main ()\n"
+                      "{\n"
+                      "  cogl_position_out = "
+                      "cogl_modelview_projection_matrix * "
+                      "cogl_position_in;\n"
+                      "  cogl_color_out = cogl_color_in;\n"
+                      "  cogl_tex_coord_out[0] = cogl_tex_coord_in;\n"
+                      "}\n");
+
+  program = cogl_create_program ();
+  cogl_program_attach_shader (program, shader);
+  cogl_program_link (program);
+
+  cogl_object_unref (shader);
+
+  /* Draw something without the program */
+  cogl_framebuffer_draw_rectangle (test_fb, pipeline,
+                                   0, 0, 50, 50);
+
+  /* Draw it again using the program. It should look exactly the same */
+  cogl_pipeline_set_user_program (pipeline, program);
+  cogl_object_unref (program);
+
+  cogl_framebuffer_draw_rectangle (test_fb, pipeline,
+                                   50, 0, 100, 50);
+  cogl_pipeline_set_user_program (pipeline, NULL);
+
+  cogl_object_unref (pipeline);
+}
+
+static void
+validate_result (CoglFramebuffer *framebuffer)
+{
+  /* Non-shader version */
+  test_utils_check_pixel (framebuffer, 25, 25, 0x00ff0000);
+  /* Shader version */
+  test_utils_check_pixel (framebuffer, 75, 25, 0x00ff0000);
+}
+
+static void
+test_just_vertex_shader (void)
+{
+  TestState state;
+
+  cogl_framebuffer_orthographic (test_fb,
+                                 0, 0,
+                                 cogl_framebuffer_get_width (test_fb),
+                                 cogl_framebuffer_get_height (test_fb),
+                                 -1,
+                                 100);
+
+  paint (&state);
+  validate_result (test_fb);
+
+  if (cogl_test_verbose ())
+    g_print ("OK\n");
+}
+
+COGL_TEST_SUITE (
+  g_test_add_func ("/just-vertex-shader", test_just_vertex_shader);
+)