add builtin GPU_SHADER_KEYFRAME_DIAMOND

Now we can draw keyframe markers as point sprites, with fewer draw calls and state changes.

Based on the builtin shader for round points with anti-aliased outline. This one is more pointy.

1 files changed, 44 insertions, 0 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_keyframe_diamond_vert.glsl b/source/blender/gpu/shaders/gpu_shader_keyframe_diamond_vert.glsl
new file mode 100644
index 00000000000..69afefa685f
--- /dev/null
+++ b/source/blender/gpu/shaders/gpu_shader_keyframe_diamond_vert.glsl
@@ -0,0 +1,44 @@
+
+uniform mat4 ModelViewProjectionMatrix;
+
+const float pixel_fudge = sqrt(2.0);
+const float outline_width = 1.25 * pixel_fudge;
+
+#if __VERSION__ == 120
+  attribute vec2 pos;
+  attribute float size;
+  attribute vec4 color;
+  attribute vec4 outlineColor;
+  varying vec4 finalColor;
+  varying vec4 finalOutlineColor;
+  varying vec4 radii;
+#else
+  in vec2 pos;
+  in float size;
+  in vec4 color;
+  in vec4 outlineColor;
+  out vec4 finalColor;
+  out vec4 finalOutlineColor;
+  out vec4 radii;
+#endif
+
+void main() {
+	gl_Position = ModelViewProjectionMatrix * vec4(pos, 0.0, 1.0);
+
+	// pass through unchanged
+	gl_PointSize = size;
+	finalColor = color;
+	finalOutlineColor = outlineColor;
+
+	// calculate concentric radii in pixels
+	float radius = 0.5 * gl_PointSize;
+
+	// start at the outside and progress toward the center
+	radii[0] = radius;
+	radii[1] = radius - pixel_fudge;
+	radii[2] = radius - outline_width;
+	radii[3] = radius - outline_width - pixel_fudge;
+
+	// convert to PointCoord units
+	radii /= size;
+}