From 212b6039ff812f59c1072384694aa85d59d2c104 Mon Sep 17 00:00:00 2001
From: Andre Weissflog <floooh@gmail.com>
Date: Mon, 12 Aug 2024 21:38:00 +0200
Subject: [PATCH] wip add test shader for
 https://github.com/floooh/sokol-tools/issues/141

---
 test/issue_141.glsl | 122 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 test/issue_141.glsl

diff --git a/test/issue_141.glsl b/test/issue_141.glsl
new file mode 100644
index 00000000..3d19cf3d
--- /dev/null
+++ b/test/issue_141.glsl
@@ -0,0 +1,122 @@
+@ctype mat4 Mat4
+@ctype vec4 Float4
+@ctype vec3 Float3
+@ctype vec2 Float2
+
+
+//
+// Mark: Layer
+//
+
+@vs layer_vs
+
+in mat2 aRotateScale;
+in mat2 aUVRotateScale;
+in vec4 aColor; // premultiplied alpha
+in vec4 aBorderColor; // premultiplied alpha
+in vec2 aUVTranslate;
+in vec2 aVertexPosition;
+in vec2 aTranslate;
+in vec2 aSize;
+in float aCornerRadius;
+in float aParam;
+in float aSamplerIndex;
+
+#define aBorderWidthOrShadowRadius aParam // sokol doesn't allow attributes names longer than 16 bytes
+
+out vec4 color;
+out vec4 borderColor; // premultiplied alpha
+out vec2 coord;
+out vec2 uv;
+out vec2 half_size;
+out float cornerRadius;
+out float borderWidthOrShadowRadius;
+out float samplerIndex;
+
+void main(void) {
+    color = aColor;
+    half_size = aSize/2.0;
+    cornerRadius = aCornerRadius;
+    borderWidthOrShadowRadius = aBorderWidthOrShadowRadius;
+    borderColor = aBorderColor;
+    samplerIndex = aSamplerIndex;
+
+    gl_Position =  vec4(aRotateScale * aVertexPosition + aTranslate, 1, 1);
+    coord = (aVertexPosition - 0.5) * aSize;
+    uv = aUVRotateScale * aVertexPosition + aUVTranslate;
+}
+@end
+
+@fs layer_fs
+#define MAX_SUPPORTED_SAMPLERS 12
+
+uniform texture2D texture0;
+uniform texture2D texture1;
+uniform texture2D texture2;
+uniform texture2D texture3;
+uniform texture2D texture4;
+uniform texture2D texture5;
+uniform texture2D texture6;
+uniform texture2D texture7;
+uniform texture2D texture8;
+uniform texture2D texture9;
+uniform texture2D texture10;
+uniform texture2D texture11;
+uniform sampler layer_sampler;
+in vec4 color; // must be premultiplied alpha
+in vec4 borderColor; // must be premultiplied alpha
+in vec2 coord;
+in vec2 uv;
+in vec2 half_size;
+in float cornerRadius;
+in float borderWidthOrShadowRadius;
+in float samplerIndex;
+
+out vec4 FragColor;
+
+float round_rect_sdf(vec2 p, vec2 rect_half_size, float radius){
+    vec2 d = abs(p) - rect_half_size + radius;
+    return min(max(d.x, d.y), 0.0) + length(max(d, 0.0)) - radius;
+}
+
+vec4 source_over(vec4 upper,vec4 lower) {
+    return upper + lower*(1.0 - upper.a);
+}
+
+void main(void) {
+
+        float b = round_rect_sdf( coord, half_size, cornerRadius );
+
+        vec4 image_color = vec4(0);
+
+        if      (samplerIndex < 0.5)  {image_color = texture(sampler2D(texture0, layer_sampler), uv);}
+        else if (samplerIndex < 1.5)  {image_color = texture(sampler2D(texture1, layer_sampler), uv);}
+        else if (samplerIndex < 2.5)  {image_color = texture(sampler2D(texture2, layer_sampler), uv);}
+        else if (samplerIndex < 3.5)  {image_color = texture(sampler2D(texture3, layer_sampler), uv);}
+        else if (samplerIndex < 4.5)  {image_color = texture(sampler2D(texture4, layer_sampler), uv);}
+        else if (samplerIndex < 5.5)  {image_color = texture(sampler2D(texture5, layer_sampler), uv);}
+        else if (samplerIndex < 6.5)  {image_color = texture(sampler2D(texture6, layer_sampler), uv);}
+        else if (samplerIndex < 7.5)  {image_color = texture(sampler2D(texture7, layer_sampler), uv);}
+        else if (samplerIndex < 8.5)  {image_color = texture(sampler2D(texture8, layer_sampler), uv);}
+        else if (samplerIndex < 9.5)  {image_color = texture(sampler2D(texture9, layer_sampler), uv);}
+        else if (samplerIndex < 10.5) {image_color = texture(sampler2D(texture10, layer_sampler), uv);}
+        else if (samplerIndex < 11.5) {image_color = texture(sampler2D(texture11, layer_sampler), uv);}
+
+        vec4 composite_color = source_over(image_color,color);
+
+
+        vec4 color_with_border = composite_color;
+        if (b+borderWidthOrShadowRadius > -1.5) {
+            vec4 border = borderColor * (clamp(b+borderWidthOrShadowRadius+1.5,0.0,1.0));
+            color_with_border = source_over(border, composite_color);
+        }
+
+        // multiplying by clamp instead of discarding works around an AMD graphics driver bug caused by
+        // using "discard" or "return", it seems any early exit from the shader triggers the bug
+        // the bug requires referencing more than one sampler in the shader and at least one of the samplers is mipmapped
+        float alpha = (1.-clamp(b+1.5,0.,1.));
+        FragColor = color_with_border * alpha;
+}
+@end
+
+@program layer layer_vs layer_fs
\ No newline at end of file