101 lines
2.7 KiB
C
101 lines
2.7 KiB
C
/*
|
|
* This sample is to demonstrate a bug where rendering an unblended
|
|
* polygon, before a series of blended ones would result in no blended
|
|
* output and incorrect depth testing
|
|
*/
|
|
|
|
#include "gl.h"
|
|
#include "glu.h"
|
|
#include "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, 1.0f); // 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
|
|
glEnable(GL_TEXTURE_2D);
|
|
glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
|
|
glDisable(GL_BLEND);
|
|
|
|
glMatrixMode(GL_PROJECTION);
|
|
glLoadIdentity(); // Reset The Projection Matrix
|
|
|
|
gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f); // Calculate The Aspect Ratio Of The Window
|
|
|
|
glMatrixMode(GL_MODELVIEW);
|
|
}
|
|
|
|
/* 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();
|
|
|
|
gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);
|
|
glMatrixMode(GL_MODELVIEW);
|
|
}
|
|
|
|
|
|
void DrawQuad(const float* colour) {
|
|
glBegin(GL_QUADS);
|
|
glColor4fv(colour);
|
|
glVertex3f(-1.0,-1.0, 0.0);
|
|
glVertex3f( 1.0,-1.0, 0.0);
|
|
glVertex3f( 1.0, 1.0, 0.0);
|
|
glVertex3f(-1.0, 1.0, 0.0);
|
|
glEnd();
|
|
}
|
|
|
|
/* The main drawing function. */
|
|
void DrawGLScene()
|
|
{
|
|
const float RED [] = {1.0, 0, 0, 0.5};
|
|
const float BLUE [] = {0.0, 0, 1, 0.5};
|
|
const float NONE [] = {0, 0, 0, 0};
|
|
|
|
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
|
|
glLoadIdentity(); // Reset The View
|
|
|
|
glTranslatef(0, 0, -10.0f); // Move Left 1.5 Units And Into The Screen 6.0
|
|
|
|
glPushMatrix();
|
|
glTranslatef(-4.0, 0, -10);
|
|
DrawQuad(RED);
|
|
glPopMatrix();
|
|
|
|
glTranslatef(4.0, 0, 0);
|
|
glEnable(GL_BLEND);
|
|
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
|
|
|
|
/* Draw 3 overlapping quads, 2 of which should be totally transparent so the
|
|
* output should be the third */
|
|
DrawQuad(NONE);
|
|
DrawQuad(NONE);
|
|
DrawQuad(BLUE);
|
|
|
|
glDisable(GL_BLEND);
|
|
|
|
glKosSwapBuffers();
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
glKosInit();
|
|
|
|
InitGL(640, 480);
|
|
ReSizeGLScene(640, 480);
|
|
|
|
while(1) {
|
|
DrawGLScene();
|
|
}
|
|
|
|
return 0;
|
|
}
|