shaders: add skia shaders

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

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

1 files changed, 62 insertions, 0 deletions

diff --git a/shaders/skia/19-85.shader_test b/shaders/skia/19-85.shader_test
new file mode 100644
index 0000000..cfe3bb5
--- /dev/null
+++ b/shaders/skia/19-85.shader_test
@@ -0,0 +1,62 @@
+[require]
+GLSL >= 1.40
+
+[fragment shader]
+#version 140
+
+out vec4 sk_FragColor;
+uniform float ucontrast_Stage2;
+uniform sampler2D uTextureSampler_0_Stage1;
+noperspective in vec2 vTransformedCoords_0_Stage0;
+flat in vec4 vcolor_Stage0;
+vec4 TextureEffect_Stage1_c0_c0(vec4 _input) {
+    vec4 _output;
+    _output = texture(uTextureSampler_0_Stage1, vTransformedCoords_0_Stage0) * _input;
+    return _output;
+}
+void main() {
+    vec4 output_Stage1;
+    {
+        output_Stage1 = TextureEffect_Stage1_c0_c0(vec4(1.0, 1.0, 1.0, 1.0));
+    }
+    vec4 output_Stage2;
+    {
+        vec4 color = output_Stage1;
+        float nonZeroAlpha = max(color.w, 9.9999997473787516e-05);
+        color = vec4(color.xyz / nonZeroAlpha, nonZeroAlpha);
+        color.xyz = color.xyz * color.xyz;
+        float luma = dot(color, vec4(0.2125999927520752, 0.71520000696182251, 0.072200000286102295, 0.0));
+        color = vec4(luma, luma, luma, 0.0);
+        if (ucontrast_Stage2 != 0.0) {
+            float m = (1.0 + ucontrast_Stage2) / (1.0 - ucontrast_Stage2);
+            float off = -0.5 * m + 0.5;
+            color = m * color + off;
+        }
+        color = clamp(color, 0.0, 1.0);
+        color.xyz = sqrt(color.xyz);
+        color.w = output_Stage1.w;
+        color.xyz *= color.w;
+        output_Stage2 = color;
+    }
+    {
+        sk_FragColor = output_Stage2;
+    }
+}
+
+[vertex shader]
+#version 140
+
+uniform vec4 sk_RTAdjust;
+uniform mat3 uCoordTransformMatrix_0_Stage0;
+in vec2 position;
+in vec4 color;
+in vec2 localCoord;
+noperspective out vec2 vTransformedCoords_0_Stage0;
+flat out vec4 vcolor_Stage0;
+void main() {
+    vTransformedCoords_0_Stage0 = (uCoordTransformMatrix_0_Stage0 * vec3(localCoord, 1.0)).xy;
+    vcolor_Stage0 = color;
+    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);
+}
+