333 lines
11 KiB
C++
333 lines
11 KiB
C++
// http://stackoverflow.com/questions/6005076/building-glew-on-windows-with-mingw
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#define GLEW_STATIC
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#include <GL/glew.h>
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#include <GLFW/glfw3.h>
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#include <SDL2/SDL.h>
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#include <SDL2/SDL_image.h>
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#include <stdio.h>
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#include <iostream>
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#include <fstream>
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#include <vector>
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#include <stdexcept>
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GLuint LoadTexture(char *filename,int *textw,int *texth) {
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SDL_Surface *surface;
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GLuint textureid;
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int mode;
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surface = IMG_Load(filename);
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// Or if you don't use SDL_image you can use SDL_LoadBMP here instead:
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// surface = SDL_LoadBMP(filename);
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// could not load filename
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if (!surface) {
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return 0;
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}
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// work out what format to tell glTexImage2D to use...
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if (surface->format->BytesPerPixel == 3) { // RGB 24bit
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mode = GL_RGB;
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} else if (surface->format->BytesPerPixel == 4) { // RGBA 32bit
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mode = GL_RGBA;
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} else {
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SDL_FreeSurface(surface);
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return 0;
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}
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*textw=surface->w;
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*texth=surface->h;
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// create one texture name
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glGenTextures(1, &textureid);
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// tell opengl to use the generated texture name
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glBindTexture(GL_TEXTURE_2D, textureid);
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// this reads from the sdl surface and puts it into an opengl texture
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glTexImage2D(GL_TEXTURE_2D, 0, mode, surface->w, surface->h, 0, mode, GL_UNSIGNED_BYTE, surface->pixels);
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// these affect how this texture is drawn later on...glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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// clean up
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SDL_FreeSurface(surface);
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return textureid;
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}
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GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path){
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// Create the shaders
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GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER);
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GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);
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// Read the Vertex Shader code from the file
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std::string VertexShaderCode;
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std::ifstream VertexShaderStream(vertex_file_path, std::ios::in);
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if(VertexShaderStream.is_open()){
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std::string Line = "";
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while(getline(VertexShaderStream, Line))
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VertexShaderCode += "\n" + Line;
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VertexShaderStream.close();
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}else{
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printf("Impossible to open %s. Are you in the right directory ? Don't forget to read the FAQ !\n", vertex_file_path);
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getchar();
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return 0;
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}
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// Read the Fragment Shader code from the file
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std::string FragmentShaderCode;
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std::ifstream FragmentShaderStream(fragment_file_path, std::ios::in);
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if(FragmentShaderStream.is_open()){
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std::string Line = "";
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while(getline(FragmentShaderStream, Line))
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FragmentShaderCode += "\n" + Line;
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FragmentShaderStream.close();
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}
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GLint Result = GL_FALSE;
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int InfoLogLength;
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// Compile Vertex Shader
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printf("Compiling shader : %s\n", vertex_file_path);
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char const * VertexSourcePointer = VertexShaderCode.c_str();
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glShaderSource(VertexShaderID, 1, &VertexSourcePointer , NULL);
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glCompileShader(VertexShaderID);
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// Check Vertex Shader
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glGetShaderiv(VertexShaderID, GL_COMPILE_STATUS, &Result);
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glGetShaderiv(VertexShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
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if ( InfoLogLength > 0 ){
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std::vector<char> VertexShaderErrorMessage(InfoLogLength+1);
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glGetShaderInfoLog(VertexShaderID, InfoLogLength, NULL, &VertexShaderErrorMessage[0]);
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printf("%s\n", &VertexShaderErrorMessage[0]);
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}
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// Compile Fragment Shader
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printf("Compiling shader : %s\n", fragment_file_path);
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char const * FragmentSourcePointer = FragmentShaderCode.c_str();
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glShaderSource(FragmentShaderID, 1, &FragmentSourcePointer , NULL);
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glCompileShader(FragmentShaderID);
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// Check Fragment Shader
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glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result);
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glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
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if ( InfoLogLength > 0 ){
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std::vector<char> FragmentShaderErrorMessage(InfoLogLength+1);
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glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]);
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printf("%s\n", &FragmentShaderErrorMessage[0]);
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}
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// Link the program
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printf("Linking program\n");
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GLuint ProgramID = glCreateProgram();
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glAttachShader(ProgramID, VertexShaderID);
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glAttachShader(ProgramID, FragmentShaderID);
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glLinkProgram(ProgramID);
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// Check the program
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glGetProgramiv(ProgramID, GL_LINK_STATUS, &Result);
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glGetProgramiv(ProgramID, GL_INFO_LOG_LENGTH, &InfoLogLength);
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if ( InfoLogLength > 0 ){
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std::vector<char> ProgramErrorMessage(InfoLogLength+1);
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glGetProgramInfoLog(ProgramID, InfoLogLength, NULL, &ProgramErrorMessage[0]);
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printf("%s\n", &ProgramErrorMessage[0]);
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}
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glDetachShader(ProgramID, VertexShaderID);
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glDetachShader(ProgramID, FragmentShaderID);
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glDeleteShader(VertexShaderID);
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glDeleteShader(FragmentShaderID);
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return ProgramID;
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}
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GLuint WriteTexture(int textw, int texth){
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// The framebuffer, which regroups 0, 1, or more textures, and 0 or 1 depth buffer.
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GLuint FramebufferName = 0;
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glGenFramebuffers(1, &FramebufferName);
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glBindFramebuffer(GL_FRAMEBUFFER, FramebufferName);
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// The texture we're going to render to
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GLuint renderedTexture;
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glGenTextures(1, &renderedTexture);
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// "Bind" the newly created texture : all future texture functions will modify this texture
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glBindTexture(GL_TEXTURE_2D, renderedTexture);
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// Give an empty image to OpenGL ( the last "0" )
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glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB, textw, texth, 0,GL_RGB, GL_UNSIGNED_BYTE, 0);
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// Poor filtering. Needed !
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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}
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int main(int argc, char* args[]) {
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GLFWwindow* window;
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GLuint tex1, tex2;
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int textw, texth;
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int textw2, texth2;
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/* Initialize the library */
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/* GLFW */
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if (!glfwInit()) {
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printf("GLFW Error");
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return 1;
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}
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/* Create a windowed mode window and its OpenGL context */
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glfwSetWindowSizeLimits(window, 640, 480, 640, 480);
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window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
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if (!window) {
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glfwTerminate();
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return 1;
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}
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/* Make the window's context current */
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glfwMakeContextCurrent(window);
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/* GLEW */
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glewExperimental = GL_FALSE;
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GLenum error = glGetError();
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if (error != GL_NO_ERROR)
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{
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std::cout << "OpenGL Error: " << error << std::endl;
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}
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GLenum glewinit = glewInit();
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if (glewinit != GLEW_OK) {
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std::cout << "Glew not okay! " << glewinit;
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return 1;
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}
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/* SDL */
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if (SDL_Init(SDL_INIT_VIDEO) < 0) {
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printf("SDL Error");
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return 1;
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}
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// INIT
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// An array of 3 vectors which represents 3 vertices
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static const GLfloat g_vertex_buffer_data[] = {
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-1.0f, -1.0f, 0.0f, // (bottom - left ) TRIANGLE 1
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1.0f, -1.0f, 0.0f, // (bottom - right)
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-1.0f, 1.0f, 0.0f, // (top - left )
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1.0f, 1.0f, 0.0f, // (top - right) TRIANGLE 2
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1.0f, -1.0f, 0.0f, // (bottom - right)
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-1.0f, 1.0f, 0.0f, // (top - left )
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};
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// One color for each vertex. They were generated randomly.
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static const GLfloat g_uv_buffer_data[] = {
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0.0f, 1.0f-0.0f, // (bottom - left ) TRIANGLE 1
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1.0f, 1.0f-0.0f, // (bottom - right)
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0.0f, 1.0f-1.0f, // (top - left )
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1.0f, 1.0f-1.0f, // (top - right) TRIANGLE 2
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1.0f, 1.0f-0.0f, // (bottom - right)
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0.0f, 1.0f-1.0f, // (top - left )
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};
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// Identify our vertex buffer
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GLuint vertexbuffer;
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glGenBuffers(1, &vertexbuffer);
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glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
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glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
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// Identify our color buffer
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GLuint colorbuffer;
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glGenBuffers(1, &colorbuffer);
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glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
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glBufferData(GL_ARRAY_BUFFER, sizeof(g_uv_buffer_data), g_uv_buffer_data, GL_STATIC_DRAW);
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tex1 = LoadTexture("../img/tests/flieger.jpg",&textw,&texth);
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printf("Tex1: %d", tex1);
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tex2 = LoadTexture("../img/tests/flieger2.jpg",&textw2,&texth2);
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printf("Tex2: %d", tex2);
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glfwSetWindowSize(window, textw, texth);
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glViewport(0, 0, textw, texth);
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glfwSetWindowSizeLimits(window, textw, texth, textw, texth);
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GLuint programID = LoadShaders("trimap.vertexshader", "trimap.fragmentshader");
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GLint textureLoc1 = glGetUniformLocation(programID, "myTextureSampler");
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GLint textureLoc2 = glGetUniformLocation(programID, "myTextureSampler2");
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GLint widthLoc = glGetUniformLocation(programID, "pixWidth");
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GLint heigthLoc = glGetUniformLocation(programID, "pixHeight");
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glActiveTexture(GL_TEXTURE0);
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glBindTexture(GL_TEXTURE_2D, tex1);
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glActiveTexture(GL_TEXTURE1);
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glBindTexture(GL_TEXTURE_2D, tex2);
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printf("Shader program ID: %d\n", programID);
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printf("textureLoc1: %d\n", textureLoc1);
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printf("textureLoc2: %d\n", textureLoc2);
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printf("widthLoc: %d\n", widthLoc);
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printf("heigthLoc: %d\n", heigthLoc);
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printf("Width: %f\n", 1.0f/textw);
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printf("Height: %f\n", 1.0f/texth);
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// INIT END
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/* Loop until the user closes the window */
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while (!glfwWindowShouldClose(window)) {
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/* Render here */
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glUseProgram(programID);
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glUniform1f(widthLoc, 1.0f/textw);
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glUniform1f(heigthLoc, 1.0f/texth);
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glUniform1i(textureLoc1, 0);
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glUniform1i(textureLoc2, 1);
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// 1rst attribute buffer : vertices
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glEnableVertexAttribArray(0);
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glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
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glVertexAttribPointer(
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0, // attribute 0. No particular reason for 0, but must match the layout in the shader.
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3, // size
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GL_FLOAT, // type
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GL_FALSE, // normalized?
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0, // stride
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(void*)0 // array buffer offset
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);
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// 2nd attribute buffer : colors
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glEnableVertexAttribArray(1);
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glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
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glVertexAttribPointer(
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1, // attribute. No particular reason for 1, but must match the layout in the shader.
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2, // size
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GL_FLOAT, // type
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GL_FALSE, // normalized?
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0, // stride
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(void*)0 // array buffer offset
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);
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// Draw the triangle !
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glDrawArrays(GL_TRIANGLES, 0, 2*3); // 2*3 indices starting at 0 -> 2 triangles -> 1 square
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glDisableVertexAttribArray(0);
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// RENDER END
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/* Swap front and back buffers */
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glfwSwapBuffers(window);
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/* Poll for and process events */
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glfwPollEvents();
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}
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glfwTerminate();
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return 0;
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}
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