/code/C/cubiverse.c

/* cubiverse.c - SDL2/OpenGL doohickey
 * by Pegasus Epsilon <pegasus@pimpninjas.org>
 * Distribute Unmodified
 */
#include <math.h>
#ifndef M_PI
	#define M_PI 3.14159265358979323846
#endif
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_opengl.h>
#undef main /* fucking SDL */
void gluPerspective (GLdouble fov, GLdouble aspect, GLdouble zNear, GLdouble zFar) {
	GLdouble xmin, xmax, ymin, ymax;
	ymin = zNear * tan(fov * M_PI / 360.0);
	ymax = -ymin;
	xmin = ymin * -aspect;
	xmax = ymax * -aspect;
	glFrustum(xmin, xmax, ymin, ymax, zNear, zFar);
}
typedef struct { GLubyte red, grn, blu; } GLubyteColor;
typedef struct { GLint x, y, z; } GLintCoord;
void loadCube (GLuint *cube) {
	GLintCoord vertices[] = {
		/* skybox version
		{1,1,1},{-1,1, 1},{1,-1,1},{-1,-1, 1},{-1,-1,-1},{-1,1, 1},{-1,1,-1},
		{1,1,1},{ 1,1,-1},{1,-1,1},{ 1,-1,-1},{-1,-1,-1},{ 1,1,-1},{-1,1,-1}
		*/
		{1,1,-1},{-1,1,-1},{1,-1,-1},{-1,-1,-1},{-1,-1,1},{-1,1,-1},{-1,1,1},
		{1,1,-1},{ 1,1, 1},{1,-1,-1},{ 1,-1, 1},{-1,-1,1},{ 1,1, 1},{-1,1,1}
	};
	GLubyteColor colors[] = {
		{255,255,255},{0,255,255},{255,0,255},{0,0,255},{0,0,0},{0,255,255},{0,255,0},
		{255,255,255},{255,255,0},{255,0,255},{255,0,0},{0,0,0},{255,255,0},{0,255,0}
	};
	*cube = glGenLists(1);
	glNewList(*cube, GL_COMPILE);
	glBegin(GL_TRIANGLE_STRIP);
	for (int i = 0; i < 14; i++) {
		glColor3ub(colors[i].red, colors[i].grn, colors[i].blu);
		glVertex3i(vertices[i].x, vertices[i].y, vertices[i].z);
	}
	glEnd();
	glEndList();
}
void resize (int width, int height) {
	GLdouble aspect = (GLfloat)width / (GLfloat)height;
	glViewport(0, 0, width, height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(45, aspect, 0.1, 40.0);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	/* FIXME: this breaks normals and does not belong here. */
	/*glScalef(.5,.5,.5);*/
	glTranslatef(0,0,-4);
}
void init (void) {
	/* antialias, son! */
	//glEnable(GL_POINT_SMOOTH);
	//glEnable(GL_LINE_SMOOTH);
	glEnable(GL_POLYGON_SMOOTH);
	glShadeModel(GL_FLAT);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glEnable(GL_BLEND);
	//glPointSize((GLfloat)1.1);
	//glLineWidth(2);
	/* yay lines */
	glPolygonMode(GL_FRONT, GL_LINE);
	/* ??? yay cargo
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LEQUAL);
	*/
}
void renderFrame (SDL_Window *window, GLuint list) {
	glClearColor(.0,.0,.0,.0);
	//glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glClear(GL_COLOR_BUFFER_BIT);
	glCallList(list);
	glFlush();
	glFinish();
	SDL_GL_SwapWindow(window);
}
int main (void) {
	SDL_Surface *screen;
	SDL_Window *window;
	SDL_GLContext deviceContext;
	GLuint cube;
	window = SDL_CreateWindow(
		"SDL2/OpenGL Demo", 0, 0, 800, 600,
		SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE |
		SDL_WINDOW_FULLSCREEN_DESKTOP | SDL_WINDOW_MAXIMIZED
	);
	if (0 > SDL_ShowCursor(0)) return 1;
	if (NULL == (screen = SDL_GetWindowSurface(window))) return 2;
	deviceContext = SDL_GL_CreateContext(window);
	resize(screen->w, screen->h);
	init();
	/* walk a cube as a single triangle strip -- fuck yeah */
	/* no normals yet */
	loadCube(&cube);
	for (;;) { /* ever */
		SDL_Event event;
		while (SDL_PollEvent(&event)) {
			switch (event.type) {
				case SDL_MOUSEMOTION:
					/* move the object
					glTranslatef(0,0,0);
					*/
					/* rotate the object */
					glRotatef(1, (float)event.motion.yrel, 0, (float)event.motion.xrel);
					SDL_WarpMouseInWindow(NULL, screen->w/2, screen->h/2);
					/* there's a function that's supposed to let us ignore the warp event
					 * but it doesn't seem to work. So instead, we eat the warp event.
					 */
					SDL_PollEvent(&event);
					break;
				case SDL_KEYDOWN:
					switch (event.key.keysym.sym) {
						case SDLK_ESCAPE:
							SDL_GL_DeleteContext(deviceContext);
							return 0;
						break;
					}
				break;
			}
		}
		renderFrame(window, cube);
	}
}
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