tests/cogl: Migrate point size attribute tests

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

src/tests/cogl/conform/meson.build

@@ -21,6 +21,7 @@ cogl_tests = [
   [ 'test-read-texture-formats', ['gl', 'gl3'] ],
   [ 'test-write-texture-formats', [] ],
   [ 'test-point-size', [] ],
+  [ 'test-point-size-attribute', [] ],
 ]
 
 cogl_test_conformance_includes = [

src/tests/cogl/conform/test-point-size-attribute.c

@@ -0,0 +1,172 @@
+#include <cogl/cogl.h>
+
+#include "tests/cogl-test-utils.h"
+
+/* This test assumes the GL driver supports point sizes up to 16
+   pixels. Cogl should probably have some way of querying the size so
+   we start from that instead */
+#define MAX_POINT_SIZE 16
+#define MIN_POINT_SIZE 4
+#define N_POINTS (MAX_POINT_SIZE - MIN_POINT_SIZE + 1)
+/* The size of the area that we'll paint each point in */
+#define POINT_BOX_SIZE (MAX_POINT_SIZE * 2)
+
+typedef struct
+{
+  float x, y;
+  float point_size;
+} PointVertex;
+
+static int
+calc_coord_offset (int pos, int pos_index, int point_size)
+{
+  switch (pos_index)
+    {
+    case 0: return pos - point_size / 2 - 2;
+    case 1: return pos - point_size / 2 + 2;
+    case 2: return pos + point_size / 2 - 2;
+    case 3: return pos + point_size / 2 + 2;
+    }
+
+  g_assert_not_reached ();
+  return 0;
+}
+
+static void
+verify_point_size (CoglFramebuffer *test_fb,
+                   int x_pos,
+                   int y_pos,
+                   int point_size)
+{
+  int y, x;
+
+  for (y = 0; y < 4; y++)
+    for (x = 0; x < 4; x++)
+      {
+        gboolean in_point = x >= 1 && x <= 2 && y >= 1 && y <= 2;
+        uint32_t expected_pixel = in_point ? 0x00ff00ff : 0xff0000ff;
+
+        test_utils_check_pixel (test_fb,
+                                calc_coord_offset (x_pos, x, point_size),
+                                calc_coord_offset (y_pos, y, point_size),
+                                expected_pixel);
+      }
+}
+
+static CoglPrimitive *
+create_primitive (const char *attribute_name)
+{
+  PointVertex vertices[N_POINTS];
+  CoglAttributeBuffer *buffer;
+  CoglAttribute *attributes[2];
+  CoglPrimitive *prim;
+  int i;
+
+  for (i = 0; i < N_POINTS; i++)
+    {
+      vertices[i].x = i * POINT_BOX_SIZE + POINT_BOX_SIZE / 2;
+      vertices[i].y = POINT_BOX_SIZE / 2;
+      vertices[i].point_size = MAX_POINT_SIZE - i;
+    }
+
+  buffer = cogl_attribute_buffer_new (test_ctx,
+                                      sizeof (vertices),
+                                      vertices);
+
+  attributes[0] = cogl_attribute_new (buffer,
+                                      "cogl_position_in",
+                                      sizeof (PointVertex),
+                                      G_STRUCT_OFFSET (PointVertex, x),
+                                      2, /* n_components */
+                                      COGL_ATTRIBUTE_TYPE_FLOAT);
+  attributes[1] = cogl_attribute_new (buffer,
+                                      attribute_name,
+                                      sizeof (PointVertex),
+                                      G_STRUCT_OFFSET (PointVertex, point_size),
+                                      1, /* n_components */
+                                      COGL_ATTRIBUTE_TYPE_FLOAT);
+
+  prim = cogl_primitive_new_with_attributes (COGL_VERTICES_MODE_POINTS,
+                                             N_POINTS,
+                                             attributes,
+                                             2 /* n_attributes */);
+
+  for (i = 0; i < 2; i++)
+    cogl_object_unref (attributes[i]);
+
+  return prim;
+}
+
+static void
+do_test (const char *attribute_name,
+         void (* pipeline_setup_func) (CoglPipeline *pipeline))
+{
+  int fb_width = cogl_framebuffer_get_width (test_fb);
+  int fb_height = cogl_framebuffer_get_height (test_fb);
+  CoglPrimitive *primitive;
+  CoglPipeline *pipeline;
+  int i;
+
+  cogl_framebuffer_orthographic (test_fb,
+                                 0, 0, /* x_1, y_1 */
+                                 fb_width, /* x_2 */
+                                 fb_height /* y_2 */,
+                                 -1, 100 /* near/far */);
+
+  cogl_framebuffer_clear4f (test_fb,
+                            COGL_BUFFER_BIT_COLOR,
+                            1.0f, 0.0f, 0.0f, 1.0f);
+
+  primitive = create_primitive (attribute_name);
+  pipeline = cogl_pipeline_new (test_ctx);
+  cogl_pipeline_set_color4ub (pipeline, 0x00, 0xff, 0x00, 0xff);
+  cogl_pipeline_set_per_vertex_point_size (pipeline, TRUE, NULL);
+  if (pipeline_setup_func)
+    pipeline_setup_func (pipeline);
+  cogl_primitive_draw (primitive, test_fb, pipeline);
+  cogl_object_unref (pipeline);
+  cogl_object_unref (primitive);
+
+  /* Verify all of the points where drawn at the right size */
+  for (i = 0; i < N_POINTS; i++)
+    verify_point_size (test_fb,
+                       i * POINT_BOX_SIZE + POINT_BOX_SIZE / 2, /* x */
+                       POINT_BOX_SIZE / 2, /* y */
+                       MAX_POINT_SIZE - i /* point size */);
+
+  if (cogl_test_verbose ())
+    g_print ("OK\n");
+}
+
+static void
+test_point_size_attribute (void)
+{
+  do_test ("cogl_point_size_in", NULL);
+}
+
+static void
+setup_snippet (CoglPipeline *pipeline)
+{
+  CoglSnippet *snippet;
+
+  snippet = cogl_snippet_new (COGL_SNIPPET_HOOK_POINT_SIZE,
+                              "attribute float "
+                              "my_super_duper_point_size_attrib;\n",
+                              NULL);
+  cogl_snippet_set_replace (snippet,
+                            "cogl_point_size_out = "
+                            "my_super_duper_point_size_attrib;\n");
+  cogl_pipeline_add_snippet (pipeline, snippet);
+  cogl_object_unref (snippet);
+}
+
+static void
+test_point_size_attribute_snippet (void)
+{
+  do_test ("my_super_duper_point_size_attrib", setup_snippet);
+}
+
+COGL_TEST_SUITE (
+  g_test_add_func ("/point-size/attribute", test_point_size_attribute);
+  g_test_add_func ("/point-size/attribute-snippet", test_point_size_attribute_snippet);
+)