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voxel-engine
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Use Geometry Shader to generate the Mesh #5

Merged
EmaMaker merged 6 commits from vram-reduce into main 2023-07-19 13:19:19 +02:00
Conversation 0 Commits 6 Files Changed 12
12 changed files with 170 additions and 168 deletions
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2
include/chunk.hpp
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@ -56,7 +56,7 @@ namespace Chunk
std::unique_ptr<Block[]> getBlocksArray(int* len) { return (this->blocks.toArray(len)); }
public:
GLuint VAO{0}, VBO{0}, EBO{0}, colorBuffer{0}, numTriangles{0};
GLuint VAO{0}, VBO{0}, extentsBuffer{0}, texinfoBuffer{0}, numVertices{0};
std::atomic<float> unload_timer{0};
private:

4
include/chunkmesher.hpp
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@ -18,8 +18,8 @@ namespace chunkmesher{
GLuint numVertices{0};
std::vector<GLfloat> vertices;
std::vector<GLfloat> colors;
std::vector<GLuint> indices;
std::vector<GLfloat> extents;
std::vector<GLfloat> texinfo;
};
oneapi::tbb::concurrent_queue<MeshData*>& getMeshDataQueue();

22
include/shader.hpp
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@ -19,31 +19,38 @@ public:
unsigned int ID;
// constructor generates the shader on the fly
// ------------------------------------------------------------------------
Shader(const char *vertexPath, const char *fragmentPath)
Shader(const char* geometryPath, const char *vertexPath, const char *fragmentPath)
{
// 1. retrieve the vertex/fragment source code from filePath
std::string vertexCode;
std::string fragmentCode;
std::string geometryCode;
std::ifstream vShaderFile;
std::ifstream fShaderFile;
std::ifstream gShaderFile;
// ensure ifstream objects can throw exceptions:
vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
gShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
try
{
// open files
vShaderFile.open(vertexPath);
fShaderFile.open(fragmentPath);
std::stringstream vShaderStream, fShaderStream;
gShaderFile.open(geometryPath);
std::stringstream vShaderStream, fShaderStream, gShaderStream;
// read file's buffer contents into streams
vShaderStream << vShaderFile.rdbuf();
fShaderStream << fShaderFile.rdbuf();
gShaderStream << gShaderFile.rdbuf();
// close file handlers
vShaderFile.close();
fShaderFile.close();
gShaderFile.close();
// convert stream into string
vertexCode = vShaderStream.str();
fragmentCode = fShaderStream.str();
geometryCode = gShaderStream.str();
}
catch (std::ifstream::failure &e)
{
@ -51,8 +58,9 @@ public:
}
const char *vShaderCode = vertexCode.c_str();
const char *fShaderCode = fragmentCode.c_str();
const char *gShaderCode = geometryCode.c_str();
// 2. compile shaders
unsigned int vertex, fragment;
unsigned int vertex, fragment, geometry;
// vertex shader
vertex = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertex, 1, &vShaderCode, NULL);
@ -63,15 +71,23 @@ public:
glShaderSource(fragment, 1, &fShaderCode, NULL);
glCompileShader(fragment);
checkCompileErrors(fragment, "FRAGMENT");
// geometry shader
geometry = glCreateShader(GL_GEOMETRY_SHADER);
glShaderSource(geometry, 1, &gShaderCode, NULL);
glCompileShader(geometry);
checkCompileErrors(geometry, "GEOMETRY");
// shader Program
ID = glCreateProgram();
glAttachShader(ID, vertex);
glAttachShader(ID, fragment);
glAttachShader(ID, geometry);
glLinkProgram(ID);
checkCompileErrors(ID, "PROGRAM");
// delete the shaders as they're linked into our program now and no longer necessary
glDeleteShader(vertex);
glDeleteShader(fragment);
glDeleteShader(geometry);
}
// activate the shader
// ------------------------------------------------------------------------

24
shaders/shader-texture.fs
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@ -2,29 +2,31 @@
out vec4 FragColor;
in vec3 vNormal;
in vec3 vTexCoord;
in vec3 TexCoord;
in vec3 Normal;
in vec3 FragPos;
vec3 lightColor = vec3(1.0);
vec3 lightDir = -normalize(vec3(0.0, 100.0, 0.0) - vec3(32.0));
float ambientStrength = 0.4;
float diffuseStrength = 0.45;
float specularStrength = 0.05;
float ambientStrength = 0.1;
float diffuseStrength = 0.8;
float specularStrength = 0.1;
uniform vec3 viewPos;
uniform float u_time;
uniform sampler2DArray textureArray;
float gamma = 2.2;
void main(){
vec3 vColor = vec3(texture(textureArray, vTexCoord));
// Load the texture
// anti-gamma-correction of the texture. Without this it would be gamma corrected twice!
vec3 vColor = pow(texture(textureArray, TexCoord).rgb, vec3(gamma));
// offset the normal a tiny bit, so that the color of faces opposing lightDir is not completely
// flat
vec3 normal = normalize(vNormal);
vec3 normal = normalize(Normal);
// Blinn-Phong lighting
/* Start of Blinn-Phong lighting */
// Ambient
vec3 ambient = lightColor*vColor;
@ -40,5 +42,5 @@ void main(){
// Final color
vec3 color = ambient * ambientStrength + diffuse * diffuseStrength + specular * specularStrength;
FragColor.rgb = color;
FragColor.rgb = pow(color, vec3(1.0/gamma));
}

80
shaders/shader-texture.gs Normal file
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@ -0,0 +1,80 @@
#version 330 core
layout (points) in;
layout (triangle_strip, max_vertices = 4) out;
in VS_OUT{
vec3 Extents;
vec3 Normal;
float BlockType;
} gs_in[];
out vec3 TexCoord;
out vec3 Normal;
out vec3 FragPos;
uniform mat4 view;
uniform mat4 projection;
void main(){
Normal = gs_in[0].Normal;
TexCoord = vec3(0.0, 0.0, gs_in[0].BlockType);
gl_Position = gl_in[0].gl_Position;
FragPos = vec3(gl_Position);
gl_Position = projection * view * gl_Position;
EmitVertex();
if(gs_in[0].Extents.x == 0){
TexCoord = vec3(0.0, gs_in[0].Extents.z, gs_in[0].BlockType);
gl_Position = gl_in[0].gl_Position + vec4(0.0, 0.0, gs_in[0].Extents.z, 0.0);
FragPos = vec3(gl_Position);
gl_Position = projection * view * gl_Position;
EmitVertex();
TexCoord = vec3(gs_in[0].Extents.y, 0.0, gs_in[0].BlockType);
gl_Position = gl_in[0].gl_Position + vec4(0.0, gs_in[0].Extents.y, 0.0, 0.0);
FragPos = vec3(gl_Position);
gl_Position = projection * view * gl_Position;
EmitVertex();
TexCoord = vec3(gs_in[0].Extents.y, gs_in[0].Extents.z, gs_in[0].BlockType);
}
else if(gs_in[0].Extents.y == 0){
TexCoord = vec3(0.0, gs_in[0].Extents.z, gs_in[0].BlockType);
gl_Position = gl_in[0].gl_Position + vec4(0.0, 0.0, gs_in[0].Extents.z, 0.0);
FragPos = vec3(gl_Position);
gl_Position = projection * view * gl_Position;
EmitVertex();
TexCoord = vec3(gs_in[0].Extents.x, 0.0, gs_in[0].BlockType);
gl_Position = gl_in[0].gl_Position + vec4(gs_in[0].Extents.x, 0.0, 0.0, 0.0);
FragPos = vec3(gl_Position);
gl_Position = projection * view * gl_Position;
EmitVertex();
TexCoord = vec3(gs_in[0].Extents.x, gs_in[0].Extents.z, gs_in[0].BlockType);
}
else{
TexCoord = vec3(gs_in[0].Extents.x, 0.0, gs_in[0].BlockType);
gl_Position = gl_in[0].gl_Position + vec4(gs_in[0].Extents.x, 0.0, 0.0, 0.0);
FragPos = vec3(gl_Position);
gl_Position = projection * view * gl_Position;
EmitVertex();
TexCoord = vec3(0.0, gs_in[0].Extents.y, gs_in[0].BlockType);
gl_Position = gl_in[0].gl_Position + vec4(0.0, gs_in[0].Extents.y, 0.0, 0.0);
FragPos = vec3(gl_Position);
gl_Position = projection * view * gl_Position;
EmitVertex();
TexCoord = vec3(gs_in[0].Extents.x, gs_in[0].Extents.y, gs_in[0].BlockType);
}
gl_Position = gl_in[0].gl_Position + vec4(gs_in[0].Extents, 0.0);
FragPos = vec3(gl_Position);
gl_Position = projection * view * gl_Position;
EmitVertex();
EndPrimitive();
}

27
shaders/shader-texture.vs
View File

@ -1,22 +1,27 @@
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;
layout (location = 2) in vec3 aTexCoord;
layout (location = 1) in vec3 aExtents;
layout (location = 2) in vec2 aInfo;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
out vec3 vNormal;
out vec3 vTexCoord;
out vec3 FragPos;
out VS_OUT {
vec3 Extents;
vec3 Normal;
float BlockType;
} vs_out;
void main()
{
vTexCoord = aTexCoord;
vNormal = mat3(transpose(inverse(model))) * aNormal;
//vNormal = mat3(transpose(inverse(model))) * aNormal;
vs_out.Extents = aExtents;
vs_out.BlockType = aInfo.y;
FragPos = vec3(model*vec4(aPos, 1.0));
gl_Position = projection * view * model * vec4(aPos, 1.0);
if(aExtents.x == 0) vs_out.Normal = vec3(1.0 - 2*aInfo.x, 0.0, 0.0);
else if(aExtents.y == 0) vs_out.Normal = vec3(0.0, 1.0 - 2*aInfo.x, 0.0);
else vs_out.Normal = vec3(0.0, 0.0, 1.0 - 2*aInfo.x);
vs_out.Normal = mat3(transpose(inverse(model))) * vs_out.Normal;
gl_Position = model * vec4(aPos, 1.0);
}

11
src/chunk.cpp
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@ -28,18 +28,17 @@ namespace Chunk
void Chunk::createBuffers(){
glGenVertexArrays(1, &(this->VAO));
glGenBuffers(1, &(this->colorBuffer));
glGenBuffers(1, &(this->VBO));
glGenBuffers(1, &(this->EBO));
glGenBuffers(1, &(this->extentsBuffer));
glGenBuffers(1, &(this->texinfoBuffer));
}
void Chunk::deleteBuffers(){
glDeleteBuffers(1, &(this->colorBuffer));
glDeleteBuffers(1, &(this->VBO));
glDeleteBuffers(1, &(this->EBO));
glDeleteBuffers(1, &(this->VBO));
glDeleteBuffers(1, &(this->extentsBuffer));
glDeleteBuffers(1, &(this->texinfoBuffer));
glDeleteVertexArrays(1, &(this->VAO));
}
Block Chunk::getBlock(int x, int y, int z)

2
src/chunkmanager.cpp
View File

@ -115,8 +115,8 @@ namespace chunkmanager
if(x > 1023 || y > 1023 || z > 1023) continue;
const uint32_t index = calculateIndex(x, y, z);
delete n;
chunks.erase(index);
//delete n;
nUnloaded++;
}
}

153
src/chunkmesher.cpp
View File

@ -41,8 +41,8 @@ void mesh(Chunk::Chunk* chunk)
mesh_data->numVertices = 0;
mesh_data->chunk = chunk;
mesh_data->vertices.clear();
mesh_data->indices.clear();
mesh_data->colors.clear();
mesh_data->extents.clear();
mesh_data->texinfo.clear();
// Abort if chunk is empty
if(chunk->getState(Chunk::CHUNK_STATE_EMPTY)){
@ -179,13 +179,19 @@ void mesh(Chunk::Chunk* chunk)
dv[2] = 0;
dv[v] = h;
quad(mesh_data, glm::vec3(x[0], x[1], x[2]),
glm::vec3(x[0] + du[0], x[1] + du[1], x[2] + du[2]),
glm::vec3(x[0] + du[0] + dv[0], x[1] + du[1] + dv[1],
x[2] + du[2] + dv[2]),
glm::vec3(x[0] + dv[0], x[1] + dv[1], x[2] + dv[2]),
glm::vec3(backFace ? q[0] : -q[0], backFace ? q[1] : -q[1], backFace ? q[2] : -q[2] ),
mask[n], dim, backFace);
// bottom left
mesh_data->vertices.push_back(x[0]); //bottomLeft.x
mesh_data->vertices.push_back(x[1]); //bottomLeft.y
mesh_data->vertices.push_back(x[2]); //bottomLeft.z
// extents, use normals for now
mesh_data->extents.push_back(du[0] + dv[0]);
mesh_data->extents.push_back(du[1] + dv[1]);
mesh_data->extents.push_back(du[2] + dv[2]);
mesh_data->texinfo.push_back(backFace ? 0.0 : 1.0);
mesh_data->texinfo.push_back((int)(mask[n]) - 2);
mesh_data->numVertices++;
}
for (l = 0; l < h; ++l)
@ -228,143 +234,36 @@ void sendtogpu(MeshData* mesh_data)
// bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
glBindVertexArray(mesh_data->chunk->VAO);
// position attribute
glBindBuffer(GL_ARRAY_BUFFER, mesh_data->chunk->VBO);
glBufferData(GL_ARRAY_BUFFER, mesh_data->vertices.size() * sizeof(GLfloat), &(mesh_data->vertices[0]), GL_STATIC_DRAW);
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
glEnableVertexAttribArray(0);
// normal attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)(3*
sizeof(float)));
glBindBuffer(GL_ARRAY_BUFFER, mesh_data->chunk->extentsBuffer);
glBufferData(GL_ARRAY_BUFFER, mesh_data->extents.size() * sizeof(GLfloat), &(mesh_data->extents[0]), GL_STATIC_DRAW);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)(0));
glEnableVertexAttribArray(1);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh_data->chunk->EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, mesh_data->indices.size() * sizeof(GLuint), &(mesh_data->indices[0]), GL_STATIC_DRAW);
// texcoords attribute
glBindBuffer(GL_ARRAY_BUFFER, mesh_data->chunk->colorBuffer);
glBufferData(GL_ARRAY_BUFFER, mesh_data->colors.size() * sizeof(GLfloat), &(mesh_data->colors[0]), GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, mesh_data->chunk->texinfoBuffer);
glBufferData(GL_ARRAY_BUFFER, mesh_data->texinfo.size() * sizeof(GLfloat), &(mesh_data->texinfo[0]), GL_STATIC_DRAW);
glEnableVertexAttribArray(2);
glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void *)0);
glBindVertexArray(0);
// save the number of indices of the mesh, it is needed later for drawing
mesh_data->chunk->numTriangles = (GLuint)(mesh_data->indices.size());
mesh_data->chunk->numVertices = (GLuint)(mesh_data->numVertices);
// once data has been sent to the GPU, it can be cleared from system RAM
mesh_data->vertices.clear();
mesh_data->indices.clear();
mesh_data->colors.clear();
mesh_data->extents.clear();
mesh_data->texinfo.clear();
}
// mark the chunk mesh has loaded on GPU
mesh_data->chunk->setState(Chunk::CHUNK_STATE_MESH_LOADED, true);
}
void quad(MeshData* mesh_data, glm::vec3 bottomLeft, glm::vec3 topLeft, glm::vec3 topRight,
glm::vec3 bottomRight, glm::vec3 normal, Block block, int dim, bool backFace)
{
mesh_data->vertices.push_back(bottomLeft.x);
mesh_data->vertices.push_back(bottomLeft.y);
mesh_data->vertices.push_back(bottomLeft.z);
mesh_data->vertices.push_back(normal.x);
mesh_data->vertices.push_back(normal.y);
mesh_data->vertices.push_back(normal.z);
mesh_data->vertices.push_back(bottomRight.x);
mesh_data->vertices.push_back(bottomRight.y);
mesh_data->vertices.push_back(bottomRight.z);
mesh_data->vertices.push_back(normal.x);
mesh_data->vertices.push_back(normal.y);
mesh_data->vertices.push_back(normal.z);
mesh_data->vertices.push_back(topLeft.x);
mesh_data->vertices.push_back(topLeft.y);
mesh_data->vertices.push_back(topLeft.z);
mesh_data->vertices.push_back(normal.x);
mesh_data->vertices.push_back(normal.y);
mesh_data->vertices.push_back(normal.z);
mesh_data->vertices.push_back(topRight.x);
mesh_data->vertices.push_back(topRight.y);
mesh_data->vertices.push_back(topRight.z);
mesh_data->vertices.push_back(normal.x);
mesh_data->vertices.push_back(normal.y);
mesh_data->vertices.push_back(normal.z);
// texcoords
if(dim == 0){
mesh_data->colors.push_back(0);
mesh_data->colors.push_back(0);
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(bottomRight.z - bottomLeft.z));
mesh_data->colors.push_back(abs(bottomRight.y - bottomLeft.y));
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(topLeft.z - bottomLeft.z));
mesh_data->colors.push_back(abs(topLeft.y - bottomLeft.y));
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(topRight.z - bottomLeft.z));
mesh_data->colors.push_back(abs(topRight.y - bottomLeft.y));
mesh_data->colors.push_back(((int)block) - 2);
}else if(dim == 1){
mesh_data->colors.push_back(0);
mesh_data->colors.push_back(0);
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(bottomRight.z - bottomLeft.z));
mesh_data->colors.push_back(abs(bottomRight.x - bottomLeft.x));
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(topLeft.z - bottomLeft.z));
mesh_data->colors.push_back(abs(topLeft.x - bottomLeft.x));
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(topRight.z - bottomLeft.z));
mesh_data->colors.push_back(abs(topRight.x - bottomLeft.x));
mesh_data->colors.push_back(((int)block) - 2);
}else{
mesh_data->colors.push_back(0);
mesh_data->colors.push_back(0);
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(bottomRight.x - bottomLeft.x));
mesh_data->colors.push_back(abs(bottomRight.y - bottomLeft.y));
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(topLeft.x - bottomLeft.x));
mesh_data->colors.push_back(abs(topLeft.y - bottomLeft.y));
mesh_data->colors.push_back(((int)block) - 2);
mesh_data->colors.push_back(abs(topRight.x - bottomLeft.x));
mesh_data->colors.push_back(abs(topRight.y - bottomLeft.y));
mesh_data->colors.push_back(((int)block) - 2);
}
if (backFace)
{
mesh_data->indices.push_back(mesh_data->numVertices + 2);
mesh_data->indices.push_back(mesh_data->numVertices);
mesh_data->indices.push_back(mesh_data->numVertices + 1);
mesh_data->indices.push_back(mesh_data->numVertices + 1);
mesh_data->indices.push_back(mesh_data->numVertices + 3);
mesh_data->indices.push_back(mesh_data->numVertices + 2);
}
else
{
mesh_data->indices.push_back(mesh_data->numVertices + 2);
mesh_data->indices.push_back(mesh_data->numVertices + 3);
mesh_data->indices.push_back(mesh_data->numVertices + 1);
mesh_data->indices.push_back(mesh_data->numVertices + 1);
mesh_data->indices.push_back(mesh_data->numVertices);
mesh_data->indices.push_back(mesh_data->numVertices + 2);
}
mesh_data->numVertices += 4;
}
};

3
src/main.cpp
View File

@ -58,7 +58,8 @@ int main()
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
glfwSetCursorPosCallback(window, mouse_callback);
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE); //GL_BACK GL_CCW by default
//glEnable(GL_FRAMEBUFFER_SRGB); //gamma correction done in fragment shader
//glEnable(GL_CULL_FACE); //GL_BACK GL_CCW by default
std::cout << "Using GPU: " << glGetString(GL_VENDOR) << " " << glGetString(GL_RENDERER) << "\n";

6
src/renderer.cpp
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@ -23,7 +23,7 @@ namespace renderer{
void init(){
// Create Shader
theShader = new Shader{"shaders/shader-texture.vs", "shaders/shader-texture.fs"};
theShader = new Shader{"shaders/shader-texture.gs", "shaders/shader-texture.vs", "shaders/shader-texture.fs"};
// Create 3d array texture
constexpr int layerCount = 3;
@ -96,14 +96,14 @@ namespace renderer{
if (!out)
{
if(c->numTriangles > 0)
if(c->numVertices > 0)
{
theShader->setMat4("model", model);
theShader->setMat4("view", theCamera.getView());
theShader->setMat4("projection", theCamera.getProjection());
glBindVertexArray(c->VAO);
glDrawElements(GL_TRIANGLES, c->numTriangles , GL_UNSIGNED_INT, 0);
glDrawArrays(GL_POINTS, 0, c->numVertices);
glBindVertexArray(0);
}
}

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