1 files changed, 29 insertions, 22 deletions

diff --git a/assets/shaders/triangle.metal b/assets/shaders/triangle.metal
index 6055705..ccb7ca7 100644
--- a/assets/shaders/triangle.metal
+++ b/assets/shaders/triangle.metal
@@ -1,33 +1,40 @@
 #include <metal_stdlib>
-
 using namespace metal;
 
-struct VertexIn {
-  float2 position;
-  float3 color;
+struct VertexData {
+    float4 position;
+    float2 texCoords;
 };
 
 struct VertexOut {
-  float4 computedPosition [[position]];
-  float3 fragColor;
-};
+    // The [[position]] attribute of this member indicates that this value
+    // is the clip space position of the vertex when this structure is
+    // returned from the vertex function.
+    float4 position [[position]];
 
-// Vertex shader
-vertex VertexOut basic_vertex(
-  const device VertexIn* vertex_array [[ buffer(0) ]],
-  unsigned int vid [[ vertex_id ]]
-  ) {
-  VertexIn v = vertex_array[vid];
+    // Since this member does not have a special attribute, the rasterizer
+    // interpolates its value with the values of the other triangle vertices
+    // and then passes the interpolated value to the fragment shader for each
+    // fragment in the triangle.
+    float2 textureCoordinate;
+};
 
-  VertexOut outVertex = VertexOut();
-  outVertex.computedPosition = float4(v.position.xy, 0.0, 1.0);
-  outVertex.fragColor = v.color;
-  return outVertex;
+vertex VertexOut
+vertexShader(uint vertexID [[vertex_id]],
+             constant VertexData* vertexData)
+{
+    VertexOut out;
+    out.position = vertexData[vertexID].position;
+    out.textureCoordinate = vertexData[vertexID].texCoords;
+    return out;
 }
 
-// Fragment shader
-fragment float4 basic_fragment(
-  VertexOut interpolated [[stage_in]]
-) { 
-  return float4(interpolated.fragColor, 1.0);
+fragment float4 fragmentShader(VertexOut in [[stage_in]],
+                               texture2d<float> colorTexture [[texture(0)]]) {
+    
+    constexpr sampler textureSampler (mag_filter::linear,
+                                      min_filter::linear);
+    // Sample the texture to obtain a color
+    const float4 colorSample = colorTexture.sample(textureSampler, in.textureCoordinate);
+    return colorSample;
 }
\ No newline at end of file