246 lines
7.2 KiB
C
246 lines
7.2 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include "GL/gl.h"
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#include "GL/glu.h"
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#include "GL/glext.h"
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#include "GL/glkos.h"
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extern uint8_t romdisk[];
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KOS_INIT_ROMDISK(romdisk);
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#ifdef __DREAMCAST__
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#define IMAGE_FILENAME "/rd/NeHe.bmp"
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#else
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#define IMAGE_FILENAME "samples/mipmap/romdisk/NeHe.bmp"
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#endif
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/* storage for one texture */
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int texture[1];
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/* Image type - contains height, width, and data */
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struct Image {
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unsigned long sizeX;
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unsigned long sizeY;
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char *data;
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};
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typedef struct Image Image;
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// quick and dirty bitmap loader...for 24 bit bitmaps with 1 plane only.
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// See http://www.dcs.ed.ac.uk/~mxr/gfx/2d/BMP.txt for more info.
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int ImageLoad(char *filename, Image *image) {
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FILE *file;
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unsigned long size; // size of the image in bytes.
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unsigned long i; // standard counter.
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unsigned short int planes; // number of planes in image (must be 1)
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unsigned short int bpp; // number of bits per pixel (must be 24)
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char temp; // temporary color storage for bgr-rgb conversion.
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// make sure the file is there.
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if ((file = fopen(filename, "rb"))==NULL)
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{
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printf("File Not Found : %s\n",filename);
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return 0;
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}
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// seek through the bmp header, up to the width/height:
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fseek(file, 18, SEEK_CUR);
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// read the width
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if ((i = fread(&image->sizeX, 4, 1, file)) != 1) {
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printf("Error reading width from %s.\n", filename);
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return 0;
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}
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printf("Width of %s: %lu\n", filename, image->sizeX);
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// read the height
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if ((i = fread(&image->sizeY, 4, 1, file)) != 1) {
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printf("Error reading height from %s.\n", filename);
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return 0;
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}
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printf("Height of %s: %lu\n", filename, image->sizeY);
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// calculate the size (assuming 24 bits or 3 bytes per pixel).
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size = image->sizeX * image->sizeY * 3;
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// read the planes
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if ((fread(&planes, 2, 1, file)) != 1) {
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printf("Error reading planes from %s.\n", filename);
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return 0;
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}
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if (planes != 1) {
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printf("Planes from %s is not 1: %u\n", filename, planes);
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return 0;
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}
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// read the bpp
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if ((i = fread(&bpp, 2, 1, file)) != 1) {
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printf("Error reading bpp from %s.\n", filename);
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return 0;
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}
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if (bpp != 24) {
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printf("Bpp from %s is not 24: %u\n", filename, bpp);
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return 0;
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}
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// seek past the rest of the bitmap header.
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fseek(file, 24, SEEK_CUR);
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// read the data.
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image->data = (char *) malloc(size);
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if (image->data == NULL) {
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printf("Error allocating memory for color-corrected image data");
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return 0;
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}
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if ((i = fread(image->data, size, 1, file)) != 1) {
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fprintf(stderr, "Error reading image data from %s.\n", filename);
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return 0;
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}
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for (i=0;i<size;i+=3) { // reverse all of the colors. (bgr -> rgb)
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temp = image->data[i];
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image->data[i] = image->data[i+2];
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image->data[i+2] = temp;
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}
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// we're done.
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return 1;
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}
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// Load Bitmaps And Convert To Textures
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void LoadGLTextures() {
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// Load Texture
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Image *image1;
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// allocate space for texture
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image1 = (Image *) malloc(sizeof(Image));
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if (image1 == NULL) {
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printf("Error allocating space for image");
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exit(0);
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}
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if (!ImageLoad(IMAGE_FILENAME, image1)) {
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exit(1);
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}
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// Create Texture
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glGenTextures(1, &texture[0]);
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glBindTexture(GL_TEXTURE_2D, texture[0]); // 2d texture (x and y size)
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); // scale linearly when image bigger than texture
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR); // scale linearly when image smalled than texture
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// 2d texture, level of detail 0 (normal), 3 components (red, green, blue), x size from image, y size from image,
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// border 0 (normal), rgb color data, unsigned byte data, and finally the data itself.
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glTexImage2D(GL_TEXTURE_2D, 0, 3, image1->sizeX, image1->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image1->data);
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glGenerateMipmapEXT(GL_TEXTURE_2D);
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free(image1);
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};
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/* A general OpenGL initialization function. Sets all of the initial parameters. */
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void InitGL(int Width, int Height) // We call this right after our OpenGL window is created.
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{
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LoadGLTextures();
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glEnable(GL_TEXTURE_2D);
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glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // This Will Clear The Background Color To Black
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glClearDepth(1.0); // Enables Clearing Of The Depth Buffer
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glDepthFunc(GL_LESS); // The Type Of Depth Test To Do
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glEnable(GL_DEPTH_TEST); // Enables Depth Testing
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glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity(); // Reset The Projection Matrix
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gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f); // Calculate The Aspect Ratio Of The Window
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glMatrixMode(GL_MODELVIEW);
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}
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/* The function called when our window is resized (which shouldn't happen, because we're fullscreen) */
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void ReSizeGLScene(int Width, int Height)
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{
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if (Height == 0) // Prevent A Divide By Zero If The Window Is Too Small
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Height = 1;
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glViewport(0, 0, Width, Height); // Reset The Current Viewport And Perspective Transformation
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);
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glMatrixMode(GL_MODELVIEW);
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}
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void DrawQuad() {
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glBegin(GL_QUADS);
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glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 0.0f); // Bottom Left Of The Texture and Quad
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glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 0.0f); // Bottom Right Of The Texture and Quad
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glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 0.0f); // Top Right Of The Texture and Quad
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glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 0.0f); // Top Left Of The Texture and Quad
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glEnd(); // done with the polygon.
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}
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static GLboolean mipmap_enabled = GL_FALSE;
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static GLuint timer = 0;
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/* The main drawing function. */
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void DrawGLScene()
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{
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timer++;
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if(timer > 60) {
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timer = 0;
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mipmap_enabled = !mipmap_enabled;
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if(mipmap_enabled) {
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printf("Enabling mipmaps!\n");
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR);
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} else {
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printf("Disabling mipmaps!\n");
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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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}
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glLoadIdentity();
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glClearColor(0.5, 0.5, 0.5, 1.0);
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glBindTexture(GL_TEXTURE_2D, texture[0]);
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glTranslatef(-1.5f, 0.0f, -4.5f);
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DrawQuad();
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glTranslatef(1.0f, 0.0f, -5.0f);
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DrawQuad();
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glTranslatef(1.5f, 0.0f, -5.0f);
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DrawQuad();
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glTranslatef(2.0f, 0.0f, -5.0f);
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DrawQuad();
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glTranslatef(3.5f, 0.0f, -5.0f);
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DrawQuad();
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glKosSwapBuffers();
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}
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int main(int argc, char **argv)
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{
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glKosInit();
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InitGL(640, 480);
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ReSizeGLScene(640, 480);
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while(1) {
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DrawGLScene();
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}
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return 0;
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}
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