From fa9190b0e59cb0c4e1aa6093013090a1452307f7 Mon Sep 17 00:00:00 2001
From: Sven Balzer <4653051+Kyuusokuna@users.noreply.github.com>
Date: Fri, 1 May 2026 19:27:57 +0200
Subject: [PATCH] remove vertex and index buffer from world shader

---
 src/main.cpp           | 33 +++++----------------------------
 src/shaders/world.wgsl | 16 ++++++++++------
 2 files changed, 15 insertions(+), 34 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index a45d1f4..9419919 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1037,34 +1037,15 @@ static bool recreate_graphics_pipelines() {
 
         WGPUShaderModule world_shader = wgpuDeviceCreateShaderModule(device, &world_shader_descriptor);
 
-        WGPUVertexAttribute vertex_buffer_attributes[] = {
-            {
-                .format         = WGPUVertexFormat_Float32x3,
-                .offset         = offsetof(Vertex, pos),
-                .shaderLocation = 0,
-            },
-            {
-                .format         = WGPUVertexFormat_Float32x2,
-                .offset         = offsetof(Vertex, uv),
-                .shaderLocation = 1,
-            },
-        };
-
         WGPUVertexAttribute instance_buffer_attributes[] = {
             {
                 .format         = WGPUVertexFormat_Uint32,
                 .offset         = 0,
-                .shaderLocation = 2,
+                .shaderLocation = 0,
             },
         };
 
         WGPUVertexBufferLayout vertex_buffer_layouts[] = {
-            {
-                .stepMode       = WGPUVertexStepMode_Vertex,
-                .arrayStride    = sizeof(Vertex),
-                .attributeCount = SDL_arraysize(vertex_buffer_attributes),
-                .attributes     = vertex_buffer_attributes,
-            },
             {
                 .stepMode       = WGPUVertexStepMode_Instance,
                 .arrayStride    = sizeof(Uint32),
@@ -2111,11 +2092,9 @@ static void render_editor(WGPURenderPassColorAttachment framebuffer) {
     { // Draw Map
         ZoneScopedN("Draw Map");
         wgpuRenderPassEncoderSetPipeline(render_pass_encoder, world_render_pipeline);
-        wgpuRenderPassEncoderSetIndexBuffer(render_pass_encoder, index_buffer, WGPUIndexFormat_Uint16, 0, WGPU_WHOLE_SIZE);
-        wgpuRenderPassEncoderSetVertexBuffer(render_pass_encoder, 0, vertex_buffer, 0, WGPU_WHOLE_SIZE);
-        wgpuRenderPassEncoderSetVertexBuffer(render_pass_encoder, 1, current_map.gpu_buffer, 0, WGPU_WHOLE_SIZE);
+        wgpuRenderPassEncoderSetVertexBuffer(render_pass_encoder, 0, current_map.gpu_buffer, 0, WGPU_WHOLE_SIZE);
         wgpuRenderPassEncoderSetBindGroup(render_pass_encoder, 1, world_bind_group, 0, NULL);
-        wgpuRenderPassEncoderDrawIndexed(render_pass_encoder, 6, current_map.size.y * current_map.size.x, 0, 0, 0);
+        wgpuRenderPassEncoderDraw(render_pass_encoder, 6, current_map.size.y * current_map.size.x, 0, 0);
     }
 
     if (show_grid) { // Draw Grid
@@ -2280,11 +2259,9 @@ static void render_game(WGPURenderPassColorAttachment framebuffer) {
     { // Draw Map
         ZoneScopedN("Draw Map");
         wgpuRenderPassEncoderSetPipeline(render_pass_encoder, world_render_pipeline);
-        wgpuRenderPassEncoderSetIndexBuffer(render_pass_encoder, index_buffer, WGPUIndexFormat_Uint16, 0, WGPU_WHOLE_SIZE);
-        wgpuRenderPassEncoderSetVertexBuffer(render_pass_encoder, 0, vertex_buffer, 0, WGPU_WHOLE_SIZE);
-        wgpuRenderPassEncoderSetVertexBuffer(render_pass_encoder, 1, current_map.gpu_buffer, 0, WGPU_WHOLE_SIZE);
+        wgpuRenderPassEncoderSetVertexBuffer(render_pass_encoder, 0, current_map.gpu_buffer, 0, WGPU_WHOLE_SIZE);
         wgpuRenderPassEncoderSetBindGroup(render_pass_encoder, 1, world_bind_group, 0, NULL);
-        wgpuRenderPassEncoderDrawIndexed(render_pass_encoder, 6, current_map.size.y * current_map.size.x, 0, 0, 0);
+        wgpuRenderPassEncoderDraw(render_pass_encoder, 6, current_map.size.y * current_map.size.x, 0, 0);
     }
 
     { // Draw Player
diff --git a/src/shaders/world.wgsl b/src/shaders/world.wgsl
index 439944c..7816bfb 100644
--- a/src/shaders/world.wgsl
+++ b/src/shaders/world.wgsl
@@ -2,13 +2,10 @@ struct VertexShaderInput {
     // Per Vertex
     @builtin(vertex_index) vertex_index: u32,
 
-    @location(0) pos: vec3<f32>,
-    @location(1) uv:  vec2<f32>,
-
     // Per Instance
     @builtin(instance_index) instance_index: u32,
 
-    @location(2) tile: u32,
+    @location(0) tile: u32,
 };
 
 struct VertexShaderOutput {
@@ -37,10 +34,17 @@ struct Per_Frame_Data {
     var output: VertexShaderOutput;
 
     let tile_pos = vec2<f32>(f32(input.instance_index % per_frame.map_width), f32(input.instance_index / per_frame.map_width)) - vec2<f32>(0.5, 0.5);
+    switch (input.vertex_index) {
+        case 0: { output.pos = vec4<f32>(tile_pos + vec2<f32>(-0.5,  0.5), 0, 1) * view_projection_matrix; output.uv = vec2<f32>(0, 0); }
+        case 1: { output.pos = vec4<f32>(tile_pos + vec2<f32>(-0.5, -0.5), 0, 1) * view_projection_matrix; output.uv = vec2<f32>(0, 1); }
+        case 2: { output.pos = vec4<f32>(tile_pos + vec2<f32>( 0.5, -0.5), 0, 1) * view_projection_matrix; output.uv = vec2<f32>(1, 1); }
+        case 3: { output.pos = vec4<f32>(tile_pos + vec2<f32>(-0.5,  0.5), 0, 1) * view_projection_matrix; output.uv = vec2<f32>(0, 0); }
+        case 4: { output.pos = vec4<f32>(tile_pos + vec2<f32>( 0.5, -0.5), 0, 1) * view_projection_matrix; output.uv = vec2<f32>(1, 1); }
+        case 5: { output.pos = vec4<f32>(tile_pos + vec2<f32>( 0.5,  0.5), 0, 1) * view_projection_matrix; output.uv = vec2<f32>(1, 0); }
+        default: {}
+    }
 
     output.tile = input.tile;
-    output.pos  = vec4<f32>(tile_pos + input.pos.xy, 0, 1) * view_projection_matrix;
-    output.uv   = input.uv;
 
     return output;
 }