transformgl.c

OpeNGL超级宝典源代码. OpeNGL超级宝典源代码.

// Transformgl.c
// OpenGL SuperBible
// Demonstrates letting OpenGL do the transformations
// Program by Richard S. Wright Jr.

#include "../../Common/OpenGLSB.h"	// System and OpenGL Stuff
#include "../../Common/GLTools.h"	// OpenGL toolkit
#include <math.h>

        
        
// Called to draw scene
void RenderScene(void)
    {
 //   GLTMatrix   transformationMatrix;   // Storeage for rotation matrix
  GLTMatrix rotationMatrix, translationMatrix, transformationMatrix;

    static GLfloat yRot = 0.0f;         // Rotation angle for animation
    yRot += 0.5f;
        
    // Clear the window with current clearing color
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        
    // Build a rotation matrix
    gltRotationMatrix(gltDegToRad(yRot), 0.0f, 1.0f, 0.0f, transformationMatrix);
    transformationMatrix[12] = 0.0f;
    transformationMatrix[13] = 0.0f;
    transformationMatrix[14] = -2.5f;
        
    glLoadMatrixf(transformationMatrix);

    gltDrawTorus(0.35f, 0.15f, 40, 20);
    
    // Do the buffer Swap
    glutSwapBuffers();
    }

// This function does any needed initialization on the rendering
// context. 
void SetupRC()
    {
    // Bluish background
    glClearColor(0.0f, 0.0f, .50f, 1.0f );
         
    // Draw everything as wire frame
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    }

///////////////////////////////////////////////////////////
// Called by GLUT library when idle (window not being
// resized or moved)
void TimerFunction(int value)
    {
    // Redraw the scene with new coordinates
    glutPostRedisplay();
    glutTimerFunc(33,TimerFunction, 1);
    }



void ChangeSize(int w, int h)
    {
    GLfloat fAspect;

    // Prevent a divide by zero, when window is too short
    // (you cant make a window of zero width).
    if(h == 0)
        h = 1;

    glViewport(0, 0, w, h);
        
    fAspect = (GLfloat)w / (GLfloat)h;

    // Reset the coordinate system before modifying
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
	
    // Set the clipping volume
    gluPerspective(35.0f, fAspect, 1.0f, 50.0f);
        
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    }

int main(int argc, char* argv[])
    {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(800,600);
    glutCreateWindow("OpenGL Transformations Demo");
    glutReshapeFunc(ChangeSize);
    glutDisplayFunc(RenderScene);

    SetupRC();
    glutTimerFunc(33, TimerFunction, 1);

    glutMainLoop();

    return 0;
    }