Steward

分享是一種喜悅、更是一種幸福

程式語言 - Simple DirectMedia Layer (SDL) - v1.2 - C/C++ - OpenGL 1.0 - Apply Multitexture

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參考資訊：
https://github.com/gamedev-net/nehe-opengl

main.c

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <SDL.h>
#include <GL/gl.h>

#define TEXCOORD(u, v) \
    glMultiTexCoord2fARB(GL_TEXTURE0_ARB, u, v); \
    glMultiTexCoord2fARB(GL_TEXTURE1_ARB, u, v)
  
int main(int argc, char *argv[])
{
    const int W = 320;
    const int H = 240;
    GLuint tex[2] = { 0 };
    GLdouble nearPlane = 0.1;
    GLdouble farPlane = 100.0;
    GLdouble top = nearPlane * tan(45.0 * 3.14159 / 360.0);
    GLdouble right = top * ((GLfloat)W / (GLfloat)H);
    SDL_Surface *bmp[2] = { 0 };
    SDL_Surface *screen = NULL;
   
    SDL_Init(SDL_INIT_VIDEO);
    screen = SDL_SetVideoMode(W, H, 16, SDL_SWSURFACE | SDL_OPENGL);
    bmp[0] = SDL_LoadBMP("main.bmp");
    bmp[1] = SDL_LoadBMP("bump.bmp");
 
    glGenTextures(2, tex);

    glActiveTextureARB(GL_TEXTURE0_ARB);
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, tex[0]);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, bmp[0]->w, bmp[0]->h, 0, GL_BGR, GL_UNSIGNED_BYTE, bmp[0]->pixels);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

    glActiveTextureARB(GL_TEXTURE1_ARB);   
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, tex[1]);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, bmp[1]->w, bmp[1]->h, 0, GL_BGR, GL_UNSIGNED_BYTE, bmp[1]->pixels);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
   
    glViewport(0, 0, W, H);
    glMatrixMode(GL_PROJECTION);
    glFrustum(-right, right, -top, top, nearPlane, farPlane); 
    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();
    glTranslatef(0.0f, 0.0f, -5.0f);
    glRotatef(45, 0.0f, 1.0f, 0.0f);
    glBegin(GL_QUADS);
        TEXCOORD(0.0f, 1.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
        TEXCOORD(1.0f, 1.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
        TEXCOORD(1.0f, 0.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
        TEXCOORD(0.0f, 0.0f); glVertex3f(-1.0f,  1.0f,  1.0f);

        TEXCOORD(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
        TEXCOORD(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
        TEXCOORD(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
        TEXCOORD(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);

        TEXCOORD(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
        TEXCOORD(1.0f, 0.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
        TEXCOORD(0.0f, 0.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
        TEXCOORD(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);

        TEXCOORD(0.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
        TEXCOORD(1.0f, 1.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
        TEXCOORD(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
        TEXCOORD(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);

        TEXCOORD(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
        TEXCOORD(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
        TEXCOORD(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
        TEXCOORD(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);

        TEXCOORD(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
        TEXCOORD(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
        TEXCOORD(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
        TEXCOORD(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
    glEnd();

    SDL_GL_SwapBuffers();
    SDL_Delay(3000);
 
    glDeleteTextures(2, tex);

    SDL_FreeSurface(bmp[0]);
    SDL_FreeSurface(bmp[1]);
    SDL_Quit();
    return 0;
}

編譯、執行

$ gcc main.c -I/usr/include/SDL -o main -lSDL -lGL
$ ./main