bool GLSLProgram::compileAndLinkShaders(const char* vertexShaderFile, const char* fragmentShaderFile) {
const char* vertexSrc = readShaderFromFile(vertexShaderFile);
const char* fragSrc = readShaderFromFile(fragmentShaderFile);
int isCompiledVS, isCompiledFS, maxLength, isLinked;
GLint shader = glCreateProgram();
int vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, (const GLchar**) &vertexSrc, 0);
glCompileShader(vertexShader);
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &isCompiledVS);
if (!isCompiledVS) {
glGetShaderiv(vertexShader, GL_INFO_LOG_LENGTH, &maxLength);
char* vertexInfoLog = new char[maxLength];
glGetShaderInfoLog(vertexShader, maxLength, &maxLength, vertexInfoLog);
printf("vertex shader: compile error: ");
printf("%s", vertexInfoLog);
delete[] vertexInfoLog;
return false;
}
// compile the fragment shader
int fragShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragShader, 1, (const GLchar**) &fragSrc, 0);
glCompileShader(fragShader);
glGetShaderiv(fragShader, GL_COMPILE_STATUS, &isCompiledFS);
if (!isCompiledFS) {
glGetShaderiv(fragShader, GL_INFO_LOG_LENGTH, &maxLength);
char* fragInfoLog = new char[maxLength];
glGetShaderInfoLog(fragShader, maxLength, &maxLength, fragInfoLog);
printf("fragment shader: compile error: ");
printf("%s", fragInfoLog);
delete[] fragInfoLog;
return false;
}
// attach and link the shaders to the program
glAttachShader(shader, vertexShader);
glAttachShader(shader, fragShader);
glLinkProgram(shader);
glGetProgramiv(shader, GL_LINK_STATUS, (int*) &isLinked);
if (!isLinked) {
glGetProgramiv(shader, GL_INFO_LOG_LENGTH, &maxLength);
char* infoLog = new char[maxLength];
glGetProgramInfoLog(shader, maxLength, &maxLength,
infoLog);
fprintf(stdout, "shader: link error: ");
printf("%s", infoLog);
delete[] infoLog;
return false;
}
mHandle = shader;
return true;
}
void Shader::loadShaders(std::string vertexFile, std::string fragmentFile)
{
// Create full relative pathes
std::string vertexPath = SHADER_PATH + vertexFile;
std::string fragmentPath = SHADER_PATH + fragmentFile;
// If already initialized, delete old program
if(programInitialized)
{
glDeleteShader(vertexHandle);
glDeleteShader(fragmentHandle);
glDeleteProgram(programHandle);
}
// Load data for vertex shader
vertexHandle = glCreateShader(GL_VERTEX_SHADER);
readShaderFromFile(vertexPath, vertexHandle);
// Load data for fragment shader
fragmentHandle = glCreateShader(GL_FRAGMENT_SHADER);
readShaderFromFile(fragmentPath, fragmentHandle);
// Bind shaders
programHandle = glCreateProgram();
glAttachShader(programHandle, vertexHandle);
glAttachShader(programHandle, fragmentHandle);
glLinkProgram(programHandle);
// Set program as initialized
programInitialized = GL_TRUE;
// Reset counter
textureSlotCounter = 0;
}
void initGL() {
// The image is displayed in the window by using two simple primitives(triangles)
// that we map to a texture. The texture will contain the colors we get from our raytracing.
glewInit();
// Create an array for holding the vertex positions of our two triangles
float positions[] = {
1.0f, -1.0f, 0.0f,
1.0f, 1.0f, 0.0f,
-1.0f, -1.0f, 0.0f,
-1.0f, 1.0f, 0.0f
};
//Create a buffer for holding our triangle vertex positions
GLuint positionBuffer;
glGenBuffers(1, &positionBuffer);
glBindBuffer(GL_ARRAY_BUFFER, positionBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW);
//Create a vertex array object
glGenVertexArrays(1, &vertexArrayObject);
glBindVertexArray(vertexArrayObject);
glBindBuffer(GL_ARRAY_BUFFER, positionBuffer);
glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);
glEnableVertexAttribArray(0);
//TODO: Init vertex/fragment shaders
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
std::string vertShaderString = readShaderFromFile("simple.vert");
std::string fragShaderString = readShaderFromFile("simple.frag");
const char *vertShaderChars = vertShaderString.c_str();
const char *fragShaderChars = fragShaderString.c_str();
glShaderSource(vertexShader, 1, &vertShaderChars, NULL);
glShaderSource(fragmentShader, 1, &fragShaderChars, NULL);
compileShader(vertexShader);
compileShader(fragmentShader);
defShaderProgram = glCreateProgram();
glAttachShader(defShaderProgram, vertexShader);
glAttachShader(defShaderProgram, fragmentShader);
// Might be counterintuitive to delete the shaders here but they live on in our shaderprogram
// so basically we just free up some unused memory.
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
glBindAttribLocation(defShaderProgram, 0, "position");
glLinkProgram(defShaderProgram);
GLint programIsLinked;
glGetProgramiv(defShaderProgram, GL_LINK_STATUS, &programIsLinked);
if (!programIsLinked) {
std::cout << "Error when linking default shader program\n";
}
//TODO: Init texture to hold tracing results(image)
//TODO:
}