Compute shaders

CMakeLists.txt

@@ -106,7 +106,7 @@ endfunction ()
 function (add_slang_shader_target TARGET)
   cmake_parse_arguments ("SHADER" "" "CHAPTER_NAME" "SOURCES" ${ARGN})
   set (SHADERS_DIR ${CHAPTER_NAME}/shaders)
-  file(GLOB HAS_COMPUTE shaders/${CHAPTER_SHADER}.comp)
+  file(GLOB HAS_COMPUTE shaders/${CHAPTER_SHADER}.comp.slang)
   set (ENTRY_POINTS -entry vertMain -entry fragMain)
   if(HAS_COMPUTE)
     list(APPEND ENTRY_POINTS -entry compMain)
@@ -155,7 +155,7 @@ function (add_chapter CHAPTER_NAME)
     endif()
 
     set (CHAPTER_SHADER_SLANG_TARGET ${CHAPTER_NAME}_slang_shader)
-    file (GLOB SHADER_SLANG_SOURCES shaders/${CHAPTER_SHADER}.slang)
+    file (GLOB SHADER_SLANG_SOURCES shaders/${CHAPTER_SHADER}*.slang)
     if(SHADER_SLANG_SOURCES)
       add_slang_shader_target( ${CHAPTER_SHADER_SLANG_TARGET} CHAPTER_NAME ${CHAPTER_NAME} SOURCES ${SHADER_SLANG_SOURCES})
       add_dependencies(${CHAPTER_NAME} ${CHAPTER_SHADER_SLANG_TARGET})
@@ -275,10 +275,10 @@ add_chapter (30_multisampling
   TEXTURES images/viking_room.png
   LIBS glm::glm tinyobjloader::tinyobjloader)
 
-# add_chapter (31_compute_shader
+add_chapter (31_compute_shader
-#   SHADER 31_shader_compute
+  SHADER 31_shader_compute
-#   LIBS glm::glm)
+  LIBS glm::glm)
-#
+
 # add_chapter (32_ecosystem_utilities
 #   SHADER 27_shader_depth
 #   MODELS models/viking_room.obj

shaders/31_shader_compute.comp.slang

@@ -0,0 +1,66 @@
+struct VSInput {
+  float2 inPosition;
+  float3 inColor;
+};
+
+struct VSOutput {
+  float4 pos : SV_Position;
+  float pointSize : SV_PointSize;
+  float3 fragColor : COLOR0;
+};
+
+struct PSInput {
+  float4 pos : SV_Position;
+  float3 fragColor : COLOR0;
+  float2 pointCoord : SV_PointCoord;
+};
+
+[shader("vertex")]
+VSOutput vertMain(VSInput input) {
+  VSOutput output;
+  output.pointSize = 14.0;
+  output.pos       = float4(input.inPosition, 1.0, 1.0);
+  output.fragColor = input.inColor.rgb;
+  return output;
+}
+
+[shader("fragment")]
+float4 fragMain(PSInput input) : SV_Target {
+  float2 coord = input.pointCoord - float2(0.5);
+  return float4(input.fragColor, 0.5 - length(coord));
+}
+
+struct Particle {
+  float2 position;
+  float2 velocity;
+  float4 color;
+};
+
+struct UniformBuffer {
+  float deltaTime;
+};
+ConstantBuffer<UniformBuffer> ubo;
+
+struct ParticleSSBO {
+  Particle particles;
+};
+StructuredBuffer<ParticleSSBO> particlesIn;
+RWStructuredBuffer<ParticleSSBO> particlesOut;
+
+[shader("compute")]
+[numthreads(256, 1, 1)]
+void compMain(uint3 threadId : SV_DispatchThreadID) {
+  uint index = threadId.x;
+
+  particlesOut[index].particles.position = particlesIn[index].particles.position +
+                                           particlesIn[index].particles.velocity.xy * ubo.deltaTime;
+  particlesOut[index].particles.velocity = particlesIn[index].particles.velocity;
+
+  // Flip movement at window border
+  if ((particlesOut[index].particles.position.x <= -1.0) || (particlesOut[index].particles.position.x >= 1.0)) {
+    particlesOut[index].particles.velocity.x = -particlesOut[index].particles.velocity.x;
+  }
+  if ((particlesOut[index].particles.position.y <= -1.0) || (particlesOut[index].particles.position.y >= 1.0)) {
+    particlesOut[index].particles.velocity.y = -particlesOut[index].particles.velocity.y;
+  }
+}