change grid shader primitive to line from triangle

src/renderer_wgpu.c

@@ -932,25 +932,12 @@ bool renderer_init(SDL_Window *window_) {
                 .entryPoint    = { .data = "main_vertex", .length = WGPU_STRLEN },
                 .constantCount = 0,
                 .constants     = NULL,
-                .bufferCount   = 1,
-                .buffers       = (WGPUVertexBufferLayout[]){
-                    {
-                        .stepMode       = WGPUVertexStepMode_Vertex,
-                        .arrayStride    = 20,
-                        .attributeCount = 1,
-                        .attributes     = (WGPUVertexAttribute[]){
-                            {
-                                .format         = WGPUVertexFormat_Float32x3,
-                                .offset         = 0,
-                                .shaderLocation = 0,
-                            },
-                        },
-                    },
-                },
+                .bufferCount   = 0,
+                .buffers       = NULL,
             },
 
             .primitive = {
-                .topology         = WGPUPrimitiveTopology_TriangleList,
+                .topology         = WGPUPrimitiveTopology_LineList,
                 .stripIndexFormat = WGPUIndexFormat_Undefined,
                 .frontFace        = WGPUFrontFace_CCW,
                 .cullMode         = WGPUCullMode_Back,
@@ -978,6 +965,10 @@ bool renderer_init(SDL_Window *window_) {
         wgpuShaderModuleRelease(shader);
     }
 
+    for (int i = 0; i < R_SHADER_COUNT; i++) {
+        SDL_assert(shaders[i]);
+    }
+
     return true;
 }