Improve and simplify shadercode (#42)

* dynamic headers

* add code construction method

* simplify GLSL uniforms

* document changes

* update screenshot

* naming consistency

Author: Vipitis

CHANGELOG.md

@@ -26,6 +26,9 @@ Added:
 Changed:
 * `ShadertoyChannel` is now more specific `ShadertoyChannelTexture` https://github.com/pygfx/shadertoy/pull/40
 
+Removed:
+* Removed GLSL uniform aliases in favor of just Shadertoy syntax https://github.com/pygfx/shadertoy/pull/42
+
 ### [v0.1.0] - 2024-01-21
 
 Fixed:

README.md

@@ -82,6 +82,25 @@ To display a shader from the website, simply provide its ID or url.
 > wgpu-shadertoy tsXBzS --resolution 1024 640
 ```
 
+### Uniforms
+The Shadertoy uniform format is directly supported for GLSL. However for WGSL the syntax is a bit different.
+
+| Shadertoy.com | GLSL | WGSL |
+|--- | --- | --- |
+| `vec4 iMouse` | `iMouse` | `i_mouse` |
+| `vec4 iDate` | `iDate` | `i_date` |
+| `vec3 iResolution` | `iResolution` | `i_resolution` |
+| `float iTime` | `iTime` | `i_time` |
+| `vec3 iChannelResolution[4]` | `iChannelResolution` | `i_channel_resolution` |
+| `float iTimeDelta` | `iTimeDelta` | `i_time_delta` |
+| `int iFrame` | `iFrame` | `i_frame` |
+| `float iFrameRate` | `iFrameRate` | `i_frame_rate` |
+| `sampler2D iChannel0..3` | `iChannel0..3` | `i_channel0..3` |
+| `sampler3D iChannel0..3` | not yet supported | not yet supported |
+| `samplerCube iChannel0..3` | not yet supported | not yet supported |
+| `float iChannelTime[4]` | not yet supported | not yet supported |
+| `float iSampleRate` | not yet supported | not yet supported |
+
 ## Status
 
 This project is still in development. Some functionality from the Shadertoy [website is missing](https://github.com/pygfx/shadertoy/issues/4) and [new features](https://github.com/pygfx/shadertoy/issues/8) are being added. See the issues to follow the development or [contribute yourself](./CONTRIBUTING.md)! For progress see the [changelog](./CHANGELOG.md).

examples/screenshots/shadertoy_star.png

@@ -60,7 +60,7 @@ def test_textures_glsl():
         vec2 uv = fragCoord/iResolution.xy;
         vec4 c0 = texture(iChannel0, 2.0*uv);
         vec4 c1 = texture(iChannel1, 3.0*uv);
-        fragColor = mix(c0,c1,abs(sin(i_time)));
+        fragColor = mix(c0,c1,abs(sin(iTime)));
     }
     """
 

tests/test_textures.py

@@ -60,18 +60,19 @@ def test_shadertoy_glsl():
     from wgpu_shadertoy import Shadertoy
 
     shader_code = """
-        void shader_main(out vec4 fragColor, vec2 frag_coord) {
-            vec2 uv = frag_coord / i_resolution.xy;
+        void mainImage(out vec4 fragColor, vec2 fragCoord) {
+            vec2 uv = fragCoord / iResolution.xy;
 
-            if ( length(frag_coord - i_mouse.xy) < 20.0 ) {
+            if ( length(fragCoord - iMouse.xy) < 20.0 ) {
                 fragColor = vec4(0.0, 0.0, 0.0, 1.0);
             }else{
-                fragColor = vec4( 0.5 + 0.5 * sin(i_time * vec3(uv, 1.0) ), 1.0);
+                fragColor = vec4( 0.5 + 0.5 * sin(iTime * vec3(uv, 1.0) ), 1.0);
             }
 
         }
     """
 
+    # tests the shader_type detection base case we will most likely see.
     shader = Shadertoy(shader_code, resolution=(800, 450))
     assert shader.resolution == (800, 450)
     assert shader.image.shader_code == shader_code
@@ -97,6 +98,7 @@ def test_shadertoy_glsl2():
         }
     """
 
+    # this tests if setting the shader_type to glsl works as expected
     shader = Shadertoy(shader_code, shader_type="glsl", resolution=(800, 450))
     assert shader.resolution == (800, 450)
     assert shader.image.shader_code == shader_code
@@ -122,6 +124,7 @@ def test_shadertoy_glsl3():
         }
     """
 
+    # this tests glsl detection against the regular expression when using more than one whitespace between void and mainImage.
     shader = Shadertoy(shader_code, resolution=(800, 450))
     assert shader.resolution == (800, 450)
     assert shader.image.shader_code == shader_code
@@ -135,13 +138,13 @@ def test_shadertoy_offscreen():
     from wgpu_shadertoy import Shadertoy
 
     shader_code = """
-        void shader_main(out vec4 fragColor, vec2 frag_coord) {
-            vec2 uv = frag_coord / i_resolution.xy;
+        void mainImage(out vec4 fragColor, vec2 fragCoord) {
+            vec2 uv = fragCoord / iResolution.xy;
 
-            if ( length(frag_coord - i_mouse.xy) < 20.0 ) {
+            if ( length(fragCoord - iMouse.xy) < 20.0 ) {
                 fragColor = vec4(0.0, 0.0, 0.0, 1.0);
             }else{
-                fragColor = vec4( 0.5 + 0.5 * sin(i_time * vec3(uv, 1.0) ), 1.0);
+                fragColor = vec4( 0.5 + 0.5 * sin(iTime * vec3(uv, 1.0) ), 1.0);
             }
 
         }
@@ -159,13 +162,13 @@ def test_shadertoy_snapshot():
     from wgpu_shadertoy import Shadertoy
 
     shader_code = """
-        void shader_main(out vec4 fragColor, vec2 frag_coord) {
-            vec2 uv = frag_coord / i_resolution.xy;
+        void mainImage(out vec4 fragColor, vec2 fragCoord) {
+            vec2 uv = fragCoord / iResolution.xy;
 
-            if ( length(frag_coord - i_mouse.xy) < 20.0 ) {
+            if ( length(fragCoord - iMouse.xy) < 20.0 ) {
                 fragColor = vec4(0.0, 0.0, 0.0, 1.0);
             }else{
-                fragColor = vec4( 0.5 + 0.5 * sin(i_time * vec3(uv, 1.0) ), 1.0);
+                fragColor = vec4( 0.5 + 0.5 * sin(iTime * vec3(uv, 1.0) ), 1.0);
             }
 
         }

tests/test_util_shadertoy.py

@@ -35,7 +35,7 @@ def sampler_settings(self) -> dict:
             wrap = "clamp-to-edge"
         settings["address_mode_u"] = wrap
         settings["address_mode_v"] = wrap
-        # we don't do 3D textures yet, but I guess ssetting this too is fine.
+        # we don't do 3D textures yet, but I guess setting this too is fine.
         settings["address_mode_w"] = wrap
         return settings
 
@@ -131,6 +131,35 @@ def _bind_groups_layout_entries(self, texture_view, sampler) -> list:
             },
         ]
 
+    def make_header(self, shader_type: str) -> str:
+        """
+        Constructs the glsl or wgsl code snippet that for the sampler and texture bindings.
+        """
+        # does this fallback ever happen?
+        if not shader_type:
+            shader_type = self.parent.shader_type
+        shader_type = shader_type.lower()
+
+        input_idx = self.channel_idx
+        binding_id = self.texture_binding
+        sampler_id = self.sampler_binding
+        if shader_type == "glsl":
+            return f"""
+            layout(binding = {binding_id}) uniform texture2D si_channel{input_idx};
+            layout(binding = {sampler_id}) uniform sampler sampler{input_idx};
+            
+            #define iChannel{input_idx} sampler2D(si_channel{input_idx}, sampler{input_idx})
+            """
+        elif shader_type == "wgsl":
+            return f"""
+            @group(0) @binding({binding_id})
+            var i_channel{input_idx}: texture_2d<f32>;
+            @group(0) @binding({sampler_id})
+            var sampler{input_idx}: sampler;
+            """
+        else:
+            raise ValueError(f"Unknown shader type: {shader_type}")
+
     def __repr__(self):
         """
         Convenience method to get a representation of this object for debugging.