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Copy pathShader.cpp
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121 lines (111 loc) · 3.06 KB
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// ----------------------------------------------------------------
// From Game Programming in C++ by Sanjay Madhav
// Copyright (C) 2017 Sanjay Madhav. All rights reserved.
//
// Released under the BSD License
// See LICENSE in root directory for full details.
// ----------------------------------------------------------------
#include "Shader.h"
#include "Texture.h"
#include <SDL/SDL.h>
#include <fstream>
#include <sstream>
Shader::Shader(): mShaderProgram(0), mVertexShader(0), mFragShader(0)
{
}
Shader::~Shader()
{
}
bool Shader::Load(const std::string& vertName, const std::string& fragName)
{
// Compile vertex and pixel shaders
if (!CompileShader(vertName, GL_VERTEX_SHADER, mVertexShader) || !CompileShader(fragName, GL_FRAGMENT_SHADER, mFragShader))
{
return false;
}
// Now create a shader program that links together the vertex/frag shaders
mShaderProgram = glCreateProgram();
glAttachShader(mShaderProgram, mVertexShader);
glAttachShader(mShaderProgram, mFragShader);
glLinkProgram(mShaderProgram);
// Verify that the program linked successfully
return IsValidProgram();
}
void Shader::Unload()
{
// Delete the program/shaders
glDeleteProgram(mShaderProgram);
glDeleteShader(mVertexShader);
glDeleteShader(mFragShader);
}
void Shader::SetActive()
{
// Set this program as the active one
glUseProgram(mShaderProgram);
}
void Shader::SetMatrixUniform(const char* name, const Matrix4& matrix)
{
// Find the uniform by this name
GLuint loc = glGetUniformLocation(mShaderProgram, name);
// Send the matrix data to the uniform
glUniformMatrix4fv(loc, 1, GL_TRUE, matrix.GetAsFloatPtr());
}
bool Shader::CompileShader(const std::string& fileName, GLenum shaderType, GLuint& outShader)
{
// Open file
std::ifstream shaderFile(fileName);
if (shaderFile.is_open())
{
// Read all the text into a string
std::stringstream sstream;
sstream << shaderFile.rdbuf();
std::string contents = sstream.str();
const char* contentsChar = contents.c_str();
// Create a shader of the specified type
outShader = glCreateShader(shaderType);
// Set the source characters and try to compile
glShaderSource(outShader, 1, &(contentsChar), nullptr);
glCompileShader(outShader);
if (!IsCompiled(outShader))
{
SDL_Log("Failed to compile shader %s", fileName.c_str());
return false;
}
}
else
{
SDL_Log("Shader file not found: %s", fileName.c_str());
return false;
}
return true;
}
bool Shader::IsCompiled(GLuint shader)
{
GLint status;
// Query the compile status
glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
if (status != GL_TRUE)
{
char buffer[512];
memset(buffer, 0, 512);
glGetShaderInfoLog(shader, 511, nullptr, buffer);
SDL_Log("GLSL Compile Failed:\n%s", buffer);
return false;
}
return true;
}
bool Shader::IsValidProgram()
{
GLint status;
// Query the link status
glGetProgramiv(mShaderProgram, GL_LINK_STATUS, &status);
if (status != GL_TRUE)
{
char buffer[512];
memset(buffer, 0, 512);
glGetProgramInfoLog(mShaderProgram, 511, nullptr, buffer);
SDL_Log("GLSL Link Status:\n%s", buffer);
return false;
}
return true;
}