91 lines
2.7 KiB
C++
91 lines
2.7 KiB
C++
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#define GL_GLEXT_PROTOTYPES
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#include <SDL/SDL.h>
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#include <GL/gl.h>
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#include <GL/glu.h>
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#include "checkGLError.h"
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#define WIDTH 500
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#define HEIGHT 500
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#define ADDR_DIFF(x, y) ((unsigned long) (y) - (unsigned long) (x))
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#define GL_CHECK(x) ({x; checkGLError();})
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void init(void)
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{
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GL_CHECK(glClearColor (0.0, 0.0, 0.0, 0.0));
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GL_CHECK(glEnable(GL_DEPTH_TEST));
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GL_CHECK(glShadeModel(GL_SMOOTH));
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GL_CHECK(glViewport(0, 0, WIDTH, HEIGHT));
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GL_CHECK(glMatrixMode(GL_PROJECTION));
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GL_CHECK(glLoadIdentity());
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gluPerspective(60.0, (GLfloat)WIDTH/(GLfloat)WIDTH, 1.0, 30.0);
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GL_CHECK(glMatrixMode(GL_MODELVIEW));
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GL_CHECK(glLoadIdentity());
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GL_CHECK(glTranslatef(0.0, 0.0, -3.6));
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}
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void display(void)
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{
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GL_CHECK(glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT));
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static const GLfloat data[][2][4] = {
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{{-0.8, -0.8, 0.0, 1.0}, {1.0, 0.0, 0.0, 1.0}},
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{{0.8, -0.8, 0.0, 1.0}, {0.0, 1.0, 0.0, 1.0}},
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{{0.8, 0.8, 0.0, 1.0}, {0.0, 0.0, 1.0, 1.0}},
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{{-0.8, 0.8, 0.0, 1.0}, {0.0, 0.4, 1.0, 1.0}}
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};
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static const GLbyte indexes[] = {1, 0, 2, 3};
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GLuint buffers[2];
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GL_CHECK(glGenBuffers(sizeof(buffers)/sizeof(buffers[0]), buffers));
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GL_CHECK(glBindBuffer(GL_ARRAY_BUFFER, buffers[0]));
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GL_CHECK(glBufferData(GL_ARRAY_BUFFER, sizeof(data), data, GL_STATIC_DRAW));
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GL_CHECK(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[1]));
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GL_CHECK(glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indexes), indexes,
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GL_STATIC_DRAW));
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GL_CHECK(glBindBuffer(GL_ARRAY_BUFFER, buffers[0]));
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GL_CHECK(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[1]));
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GL_CHECK(glVertexPointer(3, GL_FLOAT, ADDR_DIFF(&data[0], &data[1]),
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(void *) ADDR_DIFF(&data, &data[0][0][0])));
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GL_CHECK(glColorPointer(4, GL_FLOAT, ADDR_DIFF(&data[0], &data[1]),
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(void *) ADDR_DIFF(&data, &data[0][1][0])));
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GL_CHECK(glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_BYTE, NULL));
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SDL_GL_SwapBuffers();
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}
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int main(int argc, char *argv[])
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{
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if (SDL_Init(SDL_INIT_VIDEO))
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{
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printf("Failed to initialize SDL!\n");
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return 1;
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}
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atexit(SDL_Quit);
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SDL_Surface *screen;
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SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
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if (!(screen = SDL_SetVideoMode(WIDTH, HEIGHT, 16, SDL_OPENGL)))
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{
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printf("Failed to set video mode!\n");
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SDL_Quit();
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return 2;
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}
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SDL_WM_SetCaption(argv[0], argv[0]);
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init();
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display();
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SDL_Event event;
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while (SDL_WaitEvent(&event))
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{
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if (event.type == SDL_QUIT)
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break;
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else if (event.type == SDL_KEYDOWN)
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{
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if (event.key.keysym.sym == SDLK_ESCAPE)
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break;
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}
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}
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}
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