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80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
/*
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# Texture
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Use a hand crafted texture on a triangle:
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Black / Green
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Red / Blue
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TODO: there is one line of texture wrong at the left and bottom sides.
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- http://gamedev.stackexchange.com/questions/46963/how-to-avoid-texture-bleeding-in-a-texture-atlas
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- http://stackoverflow.com/questions/6023400/opengl-es-texture-coordinates-slightly-off
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*/
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#include "common_glut.h"
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static GLuint texture;
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static GLuint init_texture(void) {
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const unsigned int width = 20, height = 20;
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unsigned char *image;
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GLuint texture;
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image = common_texture_get_image(width, height);
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glEnable(GL_TEXTURE_2D);
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glGenTextures(1, &texture);
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glBindTexture(GL_TEXTURE_2D, texture);
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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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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height,
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0, GL_RGB, GL_UNSIGNED_BYTE, image);
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/* TODO also play with: */
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/*glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);*/
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/*glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);*/
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/*glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);*/
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/*gluBuild2DMipmaps(GL_TEXTURE_2D, 3, width, height, GL_RGB, GL_UNSIGNED_BYTE, image);*/
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free(image);
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return texture;
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}
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static void init(void) {
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glClearColor(1.0, 1.0, 1.0, 1.0);
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glShadeModel(GL_FLAT);
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texture = init_texture();
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}
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static void display(void) {
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glClear(GL_COLOR_BUFFER_BIT);
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glLoadIdentity();
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glBindTexture(GL_TEXTURE_2D, texture);
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glBegin(GL_TRIANGLES);
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glTexCoord2f(0.0f, 0.0f);
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glVertex3f(-0.5f, -0.5f, 0.0f);
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glTexCoord2f(4.0f, 0.0f);
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glVertex3f(0.5f, -0.5f, 0.0f);
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glTexCoord2f(0.0f, 2.0f);
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glVertex3f(0.0f, 0.5f, 0.0f);
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glEnd();
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glFlush();
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}
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static void reshape(int w, int h) {
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glViewport(0, 0, w, h);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glMatrixMode(GL_MODELVIEW);
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}
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int main(int argc, char** argv) {
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glutInit(&argc, argv);
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glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
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glutInitWindowSize(500, 500);
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glutInitWindowPosition(100, 100);
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glutCreateWindow(argv[0]);
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init();
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glutDisplayFunc(display);
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glutReshapeFunc(reshape);
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glutMainLoop();
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return EXIT_SUCCESS;
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}
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