GLdc/samples/depth_funcs_ortho/main.c

110 lines
2.8 KiB
C

#ifdef __DREAMCAST__
#include <kos.h>
#endif
#include "GL/gl.h"
#include "GL/glu.h"
#include "GL/glkos.h"
/* A general OpenGL initialization function. Sets all of the initial parameters. */
void InitGL(int Width, int Height) // We call this right after our OpenGL window is created.
{
glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // This Will Clear The Background Color To Black
glClearDepth(1.0); // Enables Clearing Of The Depth Buffer
glDepthFunc(GL_LEQUAL); // The Type Of Depth Test To Do
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
glMatrixMode(GL_PROJECTION);
glLoadIdentity(); // Reset The Projection Matrix
glOrtho(0.0, 640.0, 0.0, 480.0, 0.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
/* The function called when our window is resized (which shouldn't happen, because we're fullscreen) */
void ReSizeGLScene(int Width, int Height)
{
if (Height == 0) // Prevent A Divide By Zero If The Window Is Too Small
Height = 1;
glViewport(0, 0, Width, Height); // Reset The Current Viewport And Perspective Transformation
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, 640.0, 0.0, 480.0, 0.0, 1.0);
glMatrixMode(GL_MODELVIEW);
}
void DrawSquare(float width, float r, float g, float b, float z) {
width /= 2;
glColor3f(r, g, b);
glBegin(GL_QUADS); // start drawing a polygon (4 sided)
glVertex3f(-width, width, z); // Top Left
glVertex3f( width, width, z); // Top Right
glVertex3f( width,-width, z); // Bottom Right
glVertex3f(-width,-width, z); // Bottom Left
glEnd(); // done with the polygon
}
int check_start() {
#ifdef __DREAMCAST__
maple_device_t *cont;
cont_state_t *state;
cont = maple_enum_type(0, MAPLE_FUNC_CONTROLLER);
if(cont) {
state = (cont_state_t *)maple_dev_status(cont);
if(state)
return state->buttons & CONT_START;
}
#endif
return 0;
}
/* The main drawing function. */
void DrawGLScene()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
glLoadIdentity(); // Reset The View
// Center fo the screen.
glTranslatef(320, 240, 0);
glDepthFunc(GL_LEQUAL);
//RED over GREEN over BLUE
DrawSquare(100.0, 1.0, 0.0, 0.0, 0.0);
glTranslatef(50, 0, 0.03f);
DrawSquare(100, 0, 1, 0, 0);
glTranslatef(50, 0, 0.03f);
DrawSquare(100, 0, 0, 1, 0);
// swap buffers to display, since we're double buffered.
glKosSwapBuffers();
}
int main(int argc, char **argv)
{
glKosInit();
InitGL(640, 480);
ReSizeGLScene(640, 480);
while(1) {
if(check_start())
break;
DrawGLScene();
}
return 0;
}