Add a new compute shader bonus chapter (#320)

* Started working on compute shader bonus chapter

* Continued work on compute shader bonus chapter

* Continued work on compute shader bonus chapter

* Added code for compute sample

work-in-progress

* Added code for compute sample

Per-frame ssbos
Compute shader is now integrated and updating particles
work-in-progress

* Added code for compute sample

Nicer visuals, circular initial particle positions
work-in-progress

* Added code for compute sample

work-in-progress

* Tutorial compute queue families, submission and synchronization chapter

* Added paragraphs on sync, submit and queue familes

Rewording some paragraphs

* Rewording

Added image for workgroup and invocations compute space

* Sample for work group and dispatch counts

* Note and spec reference on queue families

* Minor additions

* Sample code uses SSBO per frame

Code cleanup
Tutotorial changed

* Added image for SSBOs per-frame reads and writes

* Conclusion

* Added note on signaled fences

* Update 11_Compute_Shader.md

* Use persistent mapped buffers

* Added links to advanced topics (tutorials, samples)

* Fixed typo

* Add note for the storage image chapter

* Added note on how to handle uneven no. of invocations using gl_GlobalInvocationID

* Added compute fence resize to tutorial

Was already present in code

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Update en/11_Compute_Shader.md

Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

* Name the actual compute related physical device limits

* Clarfiy how work group and invocation counts are specified

* Show how initial particle data is generated for the shader storage buffer s

* Restructure SSBO setup

* Indentation

* Minor touches

* fixed transposition

* Added note on std140 memory layout qualifier

---------

Co-authored-by: Marty Johnson <68354714+marty-johnson59@users.noreply.github.com>
Co-authored-by: Charles Giessen <46324611+charles-lunarg@users.noreply.github.com>

Author: 3 people

code/31_compute_shader.cpp

@@ -0,0 +1,40 @@
+#version 450
+
+struct Particle {
+	vec2 position;
+	vec2 velocity;
+    vec4 color;
+};
+
+layout (binding = 0) uniform ParameterUBO {
+    float deltaTime;
+} ubo;
+
+layout(std140, binding = 1) readonly buffer ParticleSSBOIn {
+   Particle particlesIn[ ];
+};
+
+layout(std140, binding = 2) buffer ParticleSSBOOut {
+   Particle particlesOut[ ];
+};
+
+layout (local_size_x = 256, local_size_y = 1, local_size_z = 1) in;
+
+void main() 
+{
+    uint index = gl_GlobalInvocationID.x;  
+
+    Particle particleIn = particlesIn[index];
+
+    particlesOut[index].position = particleIn.position + particleIn.velocity.xy * ubo.deltaTime;
+    particlesOut[index].velocity = particleIn.velocity;
+
+    // Flip movement at window border
+    if ((particlesOut[index].position.x <= -1.0) || (particlesOut[index].position.x >= 1.0)) {
+        particlesOut[index].velocity.x = -particlesOut[index].velocity.x;
+    }
+    if ((particlesOut[index].position.y <= -1.0) || (particlesOut[index].position.y >= 1.0)) {
+        particlesOut[index].velocity.y = -particlesOut[index].velocity.y;
+    }
+
+}

code/31_shader_compute.comp

@@ -0,0 +1,11 @@
+#version 450
+
+layout(location = 0) in vec3 fragColor;
+
+layout(location = 0) out vec4 outColor;
+
+void main() {
+
+    vec2 coord = gl_PointCoord - vec2(0.5);
+    outColor = vec4(fragColor, 0.5 - length(coord));
+}

code/31_shader_compute.frag

@@ -0,0 +1,13 @@
+#version 450
+
+layout(location = 0) in vec2 inPosition;
+layout(location = 1) in vec4 inColor;
+
+layout(location = 0) out vec3 fragColor;
+
+void main() {
+
+    gl_PointSize = 14.0;
+    gl_Position = vec4(inPosition.xy, 1.0, 1.0);
+    fragColor = inColor.rgb;
+}

code/31_shader_compute.vert

@@ -173,3 +173,7 @@ add_chapter (30_multisampling
   MODELS ../resources/viking_room.obj
   TEXTURES ../resources/viking_room.png
   LIBS glm::glm tinyobjloader::tinyobjloader)
+
+add_chapter (31_compute_shader
+  SHADER 31_shader_compute
+  LIBS glm::glm)