Render: Add and implement shader storage buffer (SSBO)

src/inferno/asset/shader.h

@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: MIT
  */
 
+#pragma once
+
 #include <cstdint> // int32_t, uint32_t
 #include <string_view>
 #include <unordered_map>

src/inferno/render/buffer.cpp

@@ -42,7 +42,7 @@ uint32_t BufferElement::getTypeGL() const
 	return BufferElement::getTypeGL(m_type);
 }
 
-uint32_t BufferElement::getTypeSize(const BufferElementType type)
+uint32_t BufferElement::getTypeSize(BufferElementType type)
 {
 	switch (type) {
 	case BufferElementType::None:
@@ -86,7 +86,7 @@ uint32_t BufferElement::getTypeSize(const BufferElementType type)
 	return 0;
 }
 
-uint32_t BufferElement::getTypeCount(const BufferElementType type)
+uint32_t BufferElement::getTypeCount(BufferElementType type)
 {
 	switch (type) {
 	case BufferElementType::None:
@@ -133,7 +133,7 @@ uint32_t BufferElement::getTypeCount(const BufferElementType type)
 	return 0;
 }
 
-uint32_t BufferElement::getTypeGL(const BufferElementType type)
+uint32_t BufferElement::getTypeGL(BufferElementType type)
 {
 	switch (type) {
 	case BufferElementType::None:
@@ -177,6 +177,58 @@ uint32_t BufferElement::getTypeGL(const BufferElementType type)
 	return 0;
 }
 
+uint32_t BufferElement::getGLTypeSize(uint32_t type)
+{
+	switch (type) {
+	case GL_BOOL:
+	case GL_INT:
+	case GL_UNSIGNED_INT:
+	case GL_FLOAT:
+		return 4;
+	case GL_BOOL_VEC2:
+	case GL_INT_VEC2:
+	case GL_UNSIGNED_INT_VEC2:
+	case GL_FLOAT_VEC2:
+		return 4 * 2;
+	case GL_BOOL_VEC3:
+	case GL_INT_VEC3:
+	case GL_UNSIGNED_INT_VEC3:
+	case GL_FLOAT_VEC3:
+		return 4 * 3;
+	case GL_BOOL_VEC4:
+	case GL_INT_VEC4:
+	case GL_UNSIGNED_INT_VEC4:
+	case GL_FLOAT_VEC4:
+		return 4 * 4;
+	case GL_FLOAT_MAT2:
+		return 4 * 2 * 2;
+	case GL_FLOAT_MAT3:
+		return 4 * 3 * 3;
+	case GL_FLOAT_MAT4:
+		return 4 * 4 * 4;
+
+	case GL_DOUBLE:
+		return 8;
+	case GL_DOUBLE_VEC2:
+		return 8 * 2;
+	case GL_DOUBLE_VEC3:
+		return 8 * 3;
+	case GL_DOUBLE_VEC4:
+		return 8 * 4;
+	case GL_DOUBLE_MAT2:
+		return 8 * 2 * 2;
+	case GL_DOUBLE_MAT3:
+		return 8 * 3 * 3;
+	case GL_DOUBLE_MAT4:
+		return 8 * 4 * 4;
+
+	default:
+		VERIFY_NOT_REACHED();
+	};
+
+	return 0;
+}
+
 // -----------------------------------------
 
 BufferLayout::BufferLayout(const std::initializer_list<BufferElement>& elements)

src/inferno/render/buffer.h

@@ -16,7 +16,7 @@ namespace Inferno {
 
 // clang-format off
 // https://www.khronos.org/opengl/wiki/Data_Type_(GLSL)
-enum class BufferElementType {
+enum class BufferElementType : uint8_t {
 	None = 0,
 	Bool, Bool2, Bool3, Bool4,                      // bvec
 	Int, Int2, Int3, Int4,                          // ivec
@@ -39,9 +39,10 @@ public:
 	uint32_t getTypeSize() const;
 	uint32_t getTypeCount() const;
 	uint32_t getTypeGL() const;
-	static uint32_t getTypeSize(const BufferElementType type);
-	static uint32_t getTypeCount(const BufferElementType type);
-	static uint32_t getTypeGL(const BufferElementType type);
+	static uint32_t getTypeSize(BufferElementType type);
+	static uint32_t getTypeCount(BufferElementType type);
+	static uint32_t getTypeGL(BufferElementType type);
+	static uint32_t getGLTypeSize(uint32_t type);
 
 	BufferElementType type() const { return m_type; }
 	std::string name() const { return m_name; }
@@ -49,11 +50,11 @@ public:
 	uint32_t offset() const { return m_offset; }
 	bool normalized() const { return m_normalized; }
 
-	void setType(const BufferElementType& type) { m_type = type; }
+	void setType(BufferElementType type) { m_type = type; }
 	void setName(const std::string& name) { m_name = name; }
-	void setSize(const uint32_t& size) { m_size = size; }
-	void setOffset(const uint32_t& offset) { m_offset = offset; }
-	void setNormalized(const bool& normalized) { m_normalized = normalized; }
+	void setSize(uint32_t size) { m_size = size; }
+	void setOffset(uint32_t offset) { m_offset = offset; }
+	void setNormalized(bool normalized) { m_normalized = normalized; }
 
 private:
 	BufferElementType m_type;

src/inferno/render/renderer.cpp

@@ -34,9 +34,6 @@ void Renderer<T>::endScene()
 
 // -----------------------------------------
 
-template<typename T>
-uint32_t Renderer<T>::m_maxSupportedTextureSlots = 0;
-
 template<typename T>
 void Renderer<T>::initialize()
 {

src/inferno/render/renderer.h

@@ -16,9 +16,10 @@
 #include "glm/ext/vector_float4.hpp"   // glm::vec4
 #include "ruc/singleton.h"
 
+#include "inferno/asset/shader.h"
+
 namespace Inferno {
 
-class Shader;
 class Texture;
 class TransformComponent;
 class VertexArray;
@@ -79,6 +80,8 @@ public:
 
 	void setEnableDepthBuffer(bool state) { m_enableDepthBuffer = state; }
 
+	uint32_t shaderID() const { return m_shader->id(); }
+
 protected:
 	Renderer() {}
 	virtual ~Renderer() { destroy(); };
@@ -106,7 +109,7 @@ protected:
 	T* m_vertexBufferPtr { nullptr };
 
 	// Texture units
-	static uint32_t m_maxSupportedTextureSlots;
+	static inline uint32_t m_maxSupportedTextureSlots { 0 };
 	uint32_t m_textureSlotIndex { 1 };
 	std::array<std::shared_ptr<Texture>, maxTextureSlots> m_textureSlots;
 

src/inferno/render/shader-storage-buffer.cpp

@@ -0,0 +1,195 @@
+/*
+ * Copyright (C) 2024 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdint> // int32_t, uint8_t, uintt32_t
+
+#include "glad/glad.h"
+#include "glm/ext/matrix_float2x2.hpp" // glm::mat2
+#include "glm/ext/matrix_float3x3.hpp" // glm::mat3
+#include "glm/ext/vector_float4.hpp"   // glm::vec4
+
+#include "inferno/render/buffer.h"
+#include "inferno/render/shader-storage-buffer.h"
+
+namespace Inferno {
+
+ShaderStorageBuffer::ShaderStorageBuffer(s)
+{
+	// Get maximum uniformbuffer bindings the GPU supports
+	int32_t maxBindingPoints = 0;
+	glGetIntegerv(GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS, &maxBindingPoints);
+	m_maxBindingPoints = static_cast<uint8_t>(maxBindingPoints);
+}
+
+ShaderStorageBuffer::~ShaderStorageBuffer()
+{
+}
+
+// -----------------------------------------
+
+// https://stackoverflow.com/questions/56512216#answer-56513136
+void ShaderStorageBuffer::setLayout(std::string_view blockName, uint8_t bindingPoint, uint32_t shaderID)
+{
+	VERIFY(bindingPoint < m_maxBindingPoints,
+	       "shader storage buffer exceeded binding points: {}/{}", bindingPoint, m_maxBindingPoints);
+
+	if (!exists(blockName)) {
+		m_blocks[blockName.data()] = {};
+	}
+
+	BufferBlock& block = m_blocks[blockName.data()];
+	block.bindingPoint = bindingPoint;
+	block.memberOffsets.clear();
+
+	glBindBuffer(GL_SHADER_STORAGE_BUFFER, block.id);
+
+	// Get the shader block index
+	uint32_t resourceIndex = glGetProgramResourceIndex(shaderID, GL_SHADER_STORAGE_BLOCK, blockName.data());
+	VERIFY(resourceIndex != GL_INVALID_INDEX, "block doesnt exist in shader: {}::{}", blockName, shaderID);
+
+	// Get the amount of member variables
+	uint32_t prop = GL_NUM_ACTIVE_VARIABLES;
+	int32_t memberCount;
+	glGetProgramResourceiv(shaderID, GL_SHADER_STORAGE_BLOCK, resourceIndex, 1, &prop, 1, nullptr, &memberCount);
+
+	// Get the indices of the members
+	prop = GL_ACTIVE_VARIABLES;
+	std::vector<int32_t> members(memberCount);
+	glGetProgramResourceiv(shaderID, GL_SHADER_STORAGE_BLOCK, resourceIndex, 1, &prop, (int32_t)members.size(), nullptr, members.data());
+
+	// Reserve memory for the names of the members
+	int32_t memberNameSize;
+	glGetProgramInterfaceiv(shaderID, GL_BUFFER_VARIABLE, GL_MAX_NAME_LENGTH, &memberNameSize);
+	std::vector<char> memberNameBuffer(memberNameSize);
+
+	int32_t lastOffset = 0;
+	int32_t lastType = 0;
+	for (int32_t i = 0; i < memberCount; i++) {
+
+		// Get name of buffer variable
+		int32_t stringLength;
+		glGetProgramResourceName(shaderID, GL_BUFFER_VARIABLE, members[i], memberNameSize, &stringLength, memberNameBuffer.data());
+		std::string memberName = std::string(memberNameBuffer.begin(), memberNameBuffer.begin() + stringLength);
+
+		// Get the other data needed for computing
+
+		uint32_t props[7] = {
+			GL_OFFSET,                 // 0
+			GL_TYPE,                   // 1
+			GL_ARRAY_SIZE,             // 2
+			GL_ARRAY_STRIDE,           // 3
+			GL_MATRIX_STRIDE,          // 4
+			GL_TOP_LEVEL_ARRAY_SIZE,   // 5
+			GL_TOP_LEVEL_ARRAY_STRIDE, // 6
+		};
+		int32_t params[7];
+		glGetProgramResourceiv(shaderID, GL_BUFFER_VARIABLE, members[i], 7, props, 7, nullptr, params);
+
+		// ruc::error("{}", memberName);
+		// ruc::error("\n    Offset: {}, type: {:#x}, arraySize: {}, arrayStride: {},\n    matrixStride: {}, top level size: {}, top level stride: {}\n",
+		//            params[0], params[1], params[2], params[3], params[4], params[5], params[6]);
+
+		// Array of structs
+		if (params[5] != 1 && params[6 != 0]) {
+			size_t bracketOpen = memberName.find_first_of('[');
+			size_t bracketClose = memberName.find_first_of(']');
+			std::string memberNameBegin = memberName.substr(0, bracketOpen);    // name: myArray[0].member -> myArray
+			std::string memberNameMember = memberName.substr(bracketClose + 1); // name: myArray[0].member -> .member
+			for (int32_t j = 0; j < params[5]; ++j) {
+				lastOffset = params[0] + (j * params[6]); // calc offset
+				lastType = params[1];
+
+				// Only add the member variant the first time its encountered
+				if (j == 0 && block.memberOffsets.find(memberNameBegin) == block.memberOffsets.end()) {
+					block.memberOffsets.emplace(memberNameBegin, lastOffset); // name: myArray
+				}
+
+				// Only add the index variant the first time its encountered
+				std::string memberNameIndex = memberNameBegin + "[" + std::to_string(j) + "]"; // name: myArray -> myArray[i]
+				if (block.memberOffsets.find(memberNameIndex) == block.memberOffsets.end()) {
+					block.memberOffsets.emplace(memberNameIndex, lastOffset);
+				}
+
+				block.memberOffsets.emplace(memberNameIndex + memberNameMember, // name: myArray -> myArray[i].member
+				                            lastOffset);
+			}
+		}
+		// Array of primitives
+		else if (params[2] != 1 && params[3] != 0) {
+			std::string memberNameBegin = memberName.substr(0, memberName.find_first_of('[')); // name: myArray[0] -> myArray
+			for (int32_t j = 0; j < params[2]; ++j) {
+				lastOffset = params[0] + (j * params[3]); // calc offset
+				lastType = params[1];
+
+				// Only add the member variant the first time its encountered
+				if (j == 0) {
+					block.memberOffsets.emplace(memberNameBegin, lastOffset); // name: myArray
+				}
+
+				block.memberOffsets.emplace(memberNameBegin + "[" + std::to_string(j) + "]", // name: myArray -> myArray[i]
+				                            lastOffset);
+			}
+		}
+		// Matrix case
+		else if (params[4] != 0) {
+			lastType = params[1];
+			lastOffset = params[0];
+			block.memberOffsets.emplace(memberName, params[0]);
+		}
+		else {
+			lastType = params[1];
+			lastOffset = params[0];
+			block.memberOffsets.emplace(memberName, params[0]);
+		}
+	}
+
+	block.size = lastOffset + BufferElement::getGLTypeSize(lastType);
+
+	glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+
+	// Results
+	// for (auto [k, v] : block.memberOffsets) {
+	// 	ruc::error("{}:{}", k, v);
+	// }
+}
+
+void ShaderStorageBuffer::create(std::string_view blockName)
+{
+	VERIFY(exists(blockName), "shader storage buffer block doesnt exist");
+
+	BufferBlock& block = m_blocks[blockName.data()];
+
+	if (block.id != 0) {
+		glDeleteBuffers(1, &block.id);
+	}
+
+	// Allocate buffer
+	block.id = UINT_MAX;
+	glGenBuffers(1, &block.id);
+	glBindBuffer(GL_SHADER_STORAGE_BUFFER, block.id);
+	glBufferData(GL_SHADER_STORAGE_BUFFER, block.size, NULL, GL_DYNAMIC_DRAW);
+	glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+
+	// Bind buffer to binding point
+	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, block.bindingPoint, block.id);
+}
+
+void ShaderStorageBuffer::setValue(std::string_view blockName, std::string_view member, bool value)
+{
+	setValue(blockName, member, static_cast<uint32_t>(value), sizeof(uint32_t));
+}
+
+void ShaderStorageBuffer::setValue(std::string_view blockName, std::string_view member, glm::mat2 value)
+{
+	setValue(blockName, member, static_cast<glm::mat4>(value), sizeof(glm::vec4) * 2);
+}
+
+void ShaderStorageBuffer::setValue(std::string_view blockName, std::string_view member, glm::mat3 value)
+{
+	setValue(blockName, member, static_cast<glm::mat4>(value), sizeof(glm::vec4) * 3);
+}
+
+} // namespace Inferno

src/inferno/render/shader-storage-buffer.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2024 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t, uint32_t
+#include <string_view>
+#include <unordered_map>
+
+#include "glad/glad.h"
+#include "glm/ext/matrix_float2x2.hpp" // glm::mat2
+#include "glm/ext/matrix_float3x3.hpp" // glm::mat3
+#include "ruc/singleton.h"
+
+#define CHECK_SET_CALL(blockName, member)                                                 \
+	VERIFY(exists(blockName), "shader storage buffer block doesnt exist: {}", blockName); \
+	const BufferBlock& block = m_blocks[blockName.data()];                                \
+	VERIFY(block.memberOffsets.find(member.data()) != block.memberOffsets.end(),          \
+	       "shader storage buffer member doesnt exist: {}", member);
+
+namespace Inferno {
+
+struct BufferBlock {
+	uint32_t id { 0 };
+	uint32_t size { 0 };
+	uint8_t bindingPoint { 0 };
+	std::unordered_map<std::string, uint32_t> memberOffsets {};
+};
+
+class ShaderStorageBuffer final : public ruc::Singleton<ShaderStorageBuffer> { // Shader Storage Buffer Object, SSBO
+public:
+	ShaderStorageBuffer(s);
+	virtual ~ShaderStorageBuffer();
+
+	void setLayout(std::string_view blockName, uint8_t bindingPoint, uint32_t shaderID);
+	void create(std::string_view blockName);
+
+	bool exists(std::string_view blockName) const { return m_blocks.find(blockName.data()) != m_blocks.end(); }
+
+	template<typename T> // Capture value by reference, instead of decaying to pointer
+	void setValue(std::string_view blockName, std::string_view member, T&& value, size_t size = 0)
+	{
+		CHECK_SET_CALL(blockName, member);
+
+		glBindBuffer(GL_SHADER_STORAGE_BUFFER, block.id);
+		glBufferSubData(GL_SHADER_STORAGE_BUFFER, block.memberOffsets.at(member.data()), (size) ? size : sizeof(T), &value);
+		glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+	}
+	// Exceptions:
+	void setValue(std::string_view blockName, std::string_view member, bool value);
+	void setValue(std::string_view blockName, std::string_view member, glm::mat2 value);
+	void setValue(std::string_view blockName, std::string_view member, glm::mat3 value);
+
+private:
+	uint8_t m_maxBindingPoints { 0 };
+	std::unordered_map<std::string, BufferBlock> m_blocks;
+};
+
+} // namespace Inferno

src/inferno/render/shader-structs.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2024 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include "glm/ext/vector_float3.hpp" // glm::vec3
+
+namespace Inferno {
+
+// Shader storage block layouts, using std430 memory layout rules
+
+#define MAX_DIRECTIONAL_LIGHTS 4
+struct alignas(16) DirectionalLightBlock {
+	alignas(16) glm::vec3 direction { 0 };
+
+	alignas(16) glm::vec3 ambient { 0 };
+	alignas(16) glm::vec3 diffuse { 0 };
+	alignas(16) glm::vec3 specular { 0 };
+};
+
+} // namespace Inferno

src/inferno/render/uniformbuffer.cpp

@@ -59,6 +59,7 @@ void Uniformbuffer::setLayout(std::string_view blockName, uint8_t bindingPoint,
 
 	UniformbufferBlock& block = m_blocks[blockName];
 	block.bindingPoint = bindingPoint;
+	block.uniformLocations.clear();
 
 	// Example block layout:
 	// - mat3

src/inferno/render/uniformbuffer.h

@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: MIT
  */
 
+#pragma once
+
 #include <cstddef> // size_t
 #include <cstdint> // uint8_t, uint32_t
 #include <string>
@@ -13,36 +15,18 @@
 #include "glad/glad.h"
 #include "glm/ext/matrix_float2x2.hpp" // glm::mat2
 #include "glm/ext/matrix_float3x3.hpp" // glm::mat3
-#include "glm/ext/vector_float3.hpp"   // glm::vec3
 #include "ruc/singleton.h"
 
 #include "inferno/render/buffer.h"
 
-#define CHECK_SET_CALL(blockName, member)                                              \
-	VERIFY(exists(blockName), "uniformbuffer block doesnt exist");                     \
+#define CHECK_UNIFORM_SET_CALL(blockName, member)                                      \
+	VERIFY(exists(blockName), "uniformbuffer block doesnt exist: {}", blockName);      \
 	const UniformbufferBlock& block = m_blocks[blockName];                             \
 	VERIFY(block.uniformLocations.find(member.data()) != block.uniformLocations.end(), \
-	       "uniformbuffer block member doesnt exist");
+	       "uniformbuffer member doesnt exist: {}", member);
 
 namespace Inferno {
 
-// Uniform block layouts, using std140 memory layout rules
-
-#define MAX_DIRECTIONAL_LIGHTS 32
-struct UniformDirectionalLight {
-	glm::vec3 direction { 0 };
-	float __padding0 { 0 };
-
-	glm::vec3 ambient { 0 };
-	float __padding1 { 0 };
-	glm::vec3 diffuse { 0 };
-	float __padding2 { 0 };
-	glm::vec3 specular { 0 };
-	float __padding3 { 0 };
-};
-
-// -----------------------------------------
-
 struct UniformbufferBlock {
 	uint32_t id { 0 };
 	uint32_t size { 0 };
@@ -62,7 +46,7 @@ public:
 	template<typename T> // Capture value by reference, instead of decaying to pointer
 	void setValue(std::string_view blockName, std::string_view member, T&& value, size_t size = 0)
 	{
-		CHECK_SET_CALL(blockName, member);
+		CHECK_UNIFORM_SET_CALL(blockName, member);
 
 		glBindBuffer(GL_UNIFORM_BUFFER, block.id);
 		glBufferSubData(GL_UNIFORM_BUFFER, block.uniformLocations.at(member.data()), (size) ? size : sizeof(T), &value);

src/inferno/system/rendersystem.cpp

@@ -16,6 +16,8 @@
 #include "inferno/render/framebuffer.h"
 #include "inferno/render/render-command.h"
 #include "inferno/render/renderer.h"
+#include "inferno/render/shader-storage-buffer.h"
+#include "inferno/render/shader-structs.h"
 #include "inferno/render/uniformbuffer.h"
 #include "inferno/system/camerasystem.h"
 #include "inferno/system/rendersystem.h"
@@ -57,16 +59,8 @@ void RenderSystem::initialize(uint32_t width, uint32_t height)
 		});
 	Uniformbuffer::the().create("Camera");
 
-	Uniformbuffer::the().setLayout(
-		"DirectionalLights",
-		{
-			.size = sizeof(UniformDirectionalLight) * MAX_DIRECTIONAL_LIGHTS,
-			.bindingPoint = 1,
-			.uniformLocations = {
-				{ "u_directionalLight", 0 },
-			},
-		});
-	Uniformbuffer::the().create("DirectionalLights");
+	ShaderStorageBuffer::the().setLayout("DirectionalLights", 0, RendererPostProcess::the().shaderID());
+	ShaderStorageBuffer::the().create("DirectionalLights");
 
 	ruc::info("RenderSystem initialized");
 }
@@ -137,15 +131,21 @@ void RenderSystem::renderGeometry()
 	Uniformbuffer::the().setValue("Camera", "u_projectionView", projection * view);
 	Uniformbuffer::the().setValue("Camera", "u_position", translate);
 
-	static UniformDirectionalLight directionalLights[1] = {
+	static DirectionalLightBlock directionalLights[2] = {
 		{
 			.direction = { -8.0f, -8.0f, -8.0f },
 			.ambient = { 0.1f, 0.1f, 0.1f },
 			.diffuse = { 1.0f, 1.0f, 1.0f },
 			.specular = { 1.0f, 1.0f, 1.0f },
 		},
+		{
+			.direction = { 8.0f, 8.0f, 8.0f },
+			.ambient = { 0.1f, 0.1f, 0.1f },
+			.diffuse = { 1.0f, 1.0f, 1.0f },
+			.specular = { 1.0f, 0.0f, 0.0f },
+		},
 	};
-	Uniformbuffer::the().setValue("DirectionalLights", "u_directionalLight", directionalLights);
+	ShaderStorageBuffer::the().setValue("DirectionalLights", "u_directionalLight", directionalLights);
 
 	auto modelView = m_registry->view<TransformComponent, ModelComponent>();