shaders: add skia shaders

Add shaders extracted from skia's unit tests[1]

[1] https://skia.org/dev/testing/testing

1 files changed, 41 insertions, 0 deletions

diff --git a/shaders/skia/52-22.shader_test b/shaders/skia/52-22.shader_test
new file mode 100644
index 0000000..fb26133
--- /dev/null
+++ b/shaders/skia/52-22.shader_test
@@ -0,0 +1,41 @@
+[require]
+GLSL >= 1.40
+
+[fragment shader]
+#version 140
+
+out vec4 sk_FragColor;
+uniform float uPixelSize_Stage1;
+uniform vec2 uRange_Stage1;
+uniform sampler2D uTextureSampler_0_Stage1;
+noperspective in vec2 vTransformedCoords_0_Stage0;
+void main() {
+    vec4 output_Stage1;
+    {
+        output_Stage1 = vec4(1.0, 1.0, 1.0, 1.0);
+        vec2 coord = vTransformedCoords_0_Stage0;
+        coord.y -= 25.0 * uPixelSize_Stage1;
+        for (int i = 0;i < 51; i++) {
+            output_Stage1 = min(output_Stage1, texture(uTextureSampler_0_Stage1, coord));
+            coord.y += uPixelSize_Stage1;
+        }
+    }
+    {
+        sk_FragColor = output_Stage1;
+    }
+}
+
+[vertex shader]
+#version 140
+
+uniform vec4 sk_RTAdjust;
+uniform mat3 uCoordTransformMatrix_0_Stage0;
+in vec2 position;
+in vec2 localCoord;
+noperspective out vec2 vTransformedCoords_0_Stage0;
+void main() {
+    vTransformedCoords_0_Stage0 = (uCoordTransformMatrix_0_Stage0 * vec3(localCoord, 1.0)).xy;
+    gl_Position = vec4(position.x, position.y, 0.0, 1.0);
+    gl_Position = vec4(gl_Position.xy * sk_RTAdjust.xz + gl_Position.ww * sk_RTAdjust.yw, 0.0, gl_Position.w);
+}
+