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#include "graphics/shader.h"
#include "graphics/graphicsdebug.h"
#include <QFile>
#include <QString>
#include <QTextStream>
#include <iostream>
Shader::Shader(const std::string &vertexPath,
const std::string &fragmentPath)
{
createProgramID();
std::vector<GLuint> shaders = {
createShaderFromString(getFileContents(vertexPath), GL_VERTEX_SHADER),
createShaderFromString(getFileContents(fragmentPath), GL_FRAGMENT_SHADER)
};
buildShaderProgramFromShaders(shaders);
discoverShaderData();
}
Shader::~Shader()
{
glDeleteProgram(m_programID);
}
Shader::Shader(Shader &&that)
: m_programID(that.m_programID),
m_attributes(std::move(that.m_attributes)),
m_uniforms(std::move(that.m_uniforms))
{
that.m_programID = 0;
}
Shader& Shader::operator=(Shader &&that)
{
this->~Shader();
m_programID = that.m_programID;
m_attributes = std::move(that.m_attributes);
m_uniforms = std::move(that.m_uniforms);
that.m_programID = 0;
return *this;
}
// ================== Regular Use
void Shader::bind() const { glUseProgram(m_programID); }
void Shader::unbind() const { glUseProgram(0); }
GLuint Shader::getUniformLocation(std::string name)
{
return glGetUniformLocation(m_programID, name.c_str());
}
GLuint Shader::getEnumeratedUniformLocation(std::string name, int index)
{
std::string n = name + "[" + std::to_string(index) + "]";
return glGetUniformLocation(m_programID, n.c_str());
}
// ================== Setting Uniforms
// Note: the overload to set matrix uniforms is in the .h file
void Shader::setUniform(const std::string &name, float f)
{
glUniform1f(m_uniforms[name], f);
}
void Shader::setUniform(const std::string &name, int i)
{
glUniform1i(m_uniforms[name], i);
}
void Shader::setUniform(const std::string &name, bool b)
{
glUniform1i(m_uniforms[name], static_cast<GLint>(b));
}
// ================== Creating the Program
void Shader::createProgramID()
{
m_programID = glCreateProgram();
}
void Shader::buildShaderProgramFromShaders(const std::vector<GLuint> &shaderHandles)
{
// Attach shaders
for (const GLuint &shaderHandle : shaderHandles) {
glAttachShader(m_programID, shaderHandle);
}
// Link program
glLinkProgram(m_programID);
checkShaderLinkStatus(m_programID);
// Detach and delete shaders
for (const GLuint &shaderHandle : shaderHandles) {
glDetachShader(m_programID, shaderHandle);
glDeleteShader(shaderHandle);
}
}
// ================== Creating Shaders From Filepaths
std::string Shader::getFileContents(std::string filepath)
{
QString filepathStr = QString::fromStdString(filepath);
QFile file(filepathStr);
if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
throw std::runtime_error(std::string("Failed to open shader: ") + filepath);
}
QTextStream stream(&file);
QString contents = stream.readAll();
file.close();
return contents.toStdString();
}
GLuint Shader::createShaderFromString(const std::string &str, GLenum shaderType)
{
GLuint shaderHandle = glCreateShader(shaderType);
// Compile shader code
const char *codePtr = str.c_str();
glShaderSource(shaderHandle, 1, &codePtr, nullptr); // Assumes code is null terminated
glCompileShader(shaderHandle);
checkShaderCompilationStatus(shaderHandle);
return shaderHandle;
}
// ================== Discovering Attributes/Uniforms/Textures
void Shader::discoverShaderData() {
discoverAttributes();
discoverUniforms();
}
void Shader::discoverAttributes() {
bind();
GLint attribCount;
glGetProgramiv(m_programID, GL_ACTIVE_ATTRIBUTES, &attribCount);
for (int i = 0; i < attribCount; i++) {
const GLsizei bufSize = 256;
GLsizei nameLength = 0;
GLint arraySize = 0;
GLenum type;
GLchar name[bufSize];
glGetActiveAttrib(m_programID, i, bufSize, &nameLength, &arraySize, &type, name);
name[std::min(nameLength, bufSize - 1)] = 0;
m_attributes[std::string(name)] = glGetAttribLocation(m_programID, name);
}
unbind();
}
void Shader::discoverUniforms() {
bind();
GLint uniformCount;
glGetProgramiv(m_programID, GL_ACTIVE_UNIFORMS, &uniformCount);
for (int i = 0; i < uniformCount; i++) {
const GLsizei bufSize = 256;
GLsizei nameLength = 0;
GLint arraySize = 0;
GLenum type;
GLchar name[bufSize];
glGetActiveUniform(m_programID, i, bufSize, &nameLength, &arraySize, &type, name);
name[std::min(nameLength, bufSize - 1)] = 0;
std::string strname(name);
if (isUniformArray(name, nameLength)) {
addUniformArray(strname, arraySize);
} else if (isTexture(type)) {
addTexture(strname);
} else {
addUniform(strname);
}
}
unbind();
}
bool Shader::isUniformArray(const GLchar *name, GLsizei nameLength) {
// Check if the last 3 characters are '[0]'
return (name[nameLength - 3] == '[') &&
(name[nameLength - 2] == '0') &&
(name[nameLength - 1] == ']');
}
bool Shader::isTexture(GLenum type) {
return (type == GL_SAMPLER_2D) ||
(type == GL_SAMPLER_CUBE);
}
void Shader::addUniformArray(const std::string &name, size_t size) {
std::string cleanName = name.substr(0, name.length() - 3);
for (auto i = static_cast<size_t>(0); i < size; i++) {
std::string enumeratedName = name;
enumeratedName[enumeratedName.length() - 2] = static_cast<char>('0' + i);
std::tuple< std::string, size_t > nameIndexTuple = std::make_tuple(cleanName, i);
m_uniformArrays[nameIndexTuple] = glGetUniformLocation(m_programID, enumeratedName.c_str());
}
#if GRAPHICS_DEBUG_LEVEL > 0
m_trackedUniformArrays[name] = false;
#endif
}
void Shader::addTexture(const std::string &name) {
GLint location = glGetUniformLocation(m_programID, name.c_str());
m_textureLocations[name] = location;
GLint slot = m_textureSlots.size();
m_textureSlots[location] = slot; // Assign slots in increasing order.
#if GRAPHICS_DEBUG_LEVEL > 0
m_trackedTextures[name] = false;
#endif
}
void Shader::addUniform(const std::string &name) {
m_uniforms[name] = glGetUniformLocation(m_programID, name.c_str());
#if GRAPHICS_DEBUG_LEVEL > 0
m_trackedUniforms[name] = false;
#endif
}
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