几个opengl实例源码

// Block.c // OpenGL SuperBible, Chapter 1 // Demonstrates an assortment of basic 3D concepts // Program by Richard S. Wright Jr. #include "../../Common/OpenGLSB.h" // System and OpenGL Stuff #include "../../Common/GLTools.h" // OpenGL toolkit #include <math.h> // Keep track of effects step int nStep = 0; // Lighting data GLfloat lightAmbient[] = { 0.2f, 0.2f, 0.2f, 1.0f }; GLfloat lightDiffuse[] = { 0.7f, 0.7f, 0.7f, 1.0f }; GLfloat lightSpecular[] = { 0.9f, 0.9f, 0.9f }; GLfloat materialColor[] = { 0.8f, 0.0f, 0.0f }; GLfloat lightpos[] = { -80.0f, 120.0f, 100.0f, 0.0f }; GLfloat ground[3][3] = { { 0.0f, -25.0f, 0.0f }, { 10.0f, -25.0f, 0.0f }, { 10.0f, -25.0f, -10.0f } }; GLuint textures[4]; // Reduces a normal vector specified as a set of three coordinates, // to a unit normal vector of length one. void ReduceToUnit(float vector[3]) { float length; // Calculate the length of the vector length = (float)sqrt((vector[0]*vector[0]) + (vector[1]*vector[1]) + (vector[2]*vector[2])); // Keep the program from blowing up by providing an exceptable // value for vectors that may calculated too close to zero. if(length == 0.0f) length = 1.0f; // Dividing each element by the length will result in a // unit normal vector. vector[0] /= length; vector[1] /= length; vector[2] /= length; } // Points p1, p2, & p3 specified in counter clock-wise order void calcNormal(float v[3][3], float out[3]) { float v1[3],v2[3]; static const int x = 0; static const int y = 1; static const int z = 2; // Calculate two vectors from the three points v1[x] = v[0][x] - v[1][x]; v1[y] = v[0][y] - v[1][y]; v1[z] = v[0][z] - v[1][z]; v2[x] = v[1][x] - v[2][x]; v2[y] = v[1][y] - v[2][y]; v2[z] = v[1][z] - v[2][z]; // Take the cross product of the two vectors to get // the normal vector which will be stored in out out[x] = v1[y]*v2[z] - v1[z]*v2[y]; out[y] = v1[z]*v2[x] - v1[x]*v2[z]; out[z] = v1[x]*v2[y] - v1[y]*v2[x]; // Normalize the vector (shorten length to one) ReduceToUnit(out); } // Creates a shadow projection matrix out of the plane equation // coefficients and the position of the light. The return value is stored // in destMat[][] void MakeShadowMatrix(GLfloat points[3][3], GLfloat lightPos[4], GLfloat destMat[4][4]) { GLfloat planeCoeff[4]; GLfloat dot; // Find the plane equation coefficients // Find the first three coefficients the same way we // find a normal. calcNormal(points,planeCoeff); // Find the last coefficient by back substitutions planeCoeff[3] = - ( (planeCoeff[0]*points[2][0]) + (planeCoeff[1]*points[2][1]) + (planeCoeff[2]*points[2][2])); // Dot product of plane and light position dot = planeCoeff[0] * lightPos[0] + planeCoeff[1] * lightPos[1] + planeCoeff[2] * lightPos[2] + planeCoeff[3] * lightPos[3]; // Now do the projection // First column destMat[0][0] = dot - lightPos[0] * planeCoeff[0]; destMat[1][0] = 0.0f - lightPos[0] * planeCoeff[1]; destMat[2][0] = 0.0f - lightPos[0] * planeCoeff[2]; destMat[3][0] = 0.0f - lightPos[0] * planeCoeff[3]; // Second column destMat[0][1] = 0.0f - lightPos[1] * planeCoeff[0]; destMat[1][1] = dot - lightPos[1] * planeCoeff[1]; destMat[2][1] = 0.0f - lightPos[1] * planeCoeff[2]; destMat[3][1] = 0.0f - lightPos[1] * planeCoeff[3]; // Third Column destMat[0][2] = 0.0f - lightPos[2] * planeCoeff[0]; destMat[1][2] = 0.0f - lightPos[2] * planeCoeff[1]; destMat[2][2] = dot - lightPos[2] * planeCoeff[2]; destMat[3][2] = 0.0f - lightPos[2] * planeCoeff[3]; // Fourth Column destMat[0][3] = 0.0f - lightPos[3] * planeCoeff[0]; destMat[1][3] = 0.0f - lightPos[3] * planeCoeff[1]; destMat[2][3] = 0.0f - lightPos[3] * planeCoeff[2]; destMat[3][3] = dot - lightPos[3] * planeCoeff[3]; } // Called to draw scene void RenderScene(void) { GLfloat cubeXform[4][4]; // Clear the window with current clearing color glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glShadeModel(GL_SMOOTH); glEnable(GL_NORMALIZE); glPushMatrix(); // Draw plane that the cube rests on glDisable(GL_LIGHTING); if(nStep == 5) { glColor3ub(255,255,255); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, textures[0]); glBegin(GL_QUADS); glTexCoord2f(0.0f, 0.0f); glVertex3f(-100.0f, -25.3f, -100.0f); glTexCoord2f(0.0f, 1.0f); glVertex3f(-100.0f, -25.3f, 100.0f); glTexCoord2f(1.0f, 1.0f); glVertex3f(100.0f, -25.3f, 100.0f); glTexCoord2f(1.0f, 0.0f); glVertex3f(100.0f, -25.3f, -100.0f); glEnd(); } else { glColor3f(0.0f, 0.0f, 0.90f); // Blue glBegin(GL_QUADS); glVertex3f(-100.0f, -25.3f, -100.0f); glVertex3f(-100.0f, -25.3f, 100.0f); glVertex3f(100.0f, -25.3f, 100.0f); glVertex3f(100.0f, -25.3f, -100.0f); glEnd(); } // Set drawing color to Red glColor3f(1.0f, 0.0f, 0.0f); // Enable, disable lighting if(nStep > 2) { glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); glEnable(GL_COLOR_MATERIAL); glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmbient); glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDiffuse); glLightfv(GL_LIGHT0, GL_SPECULAR, lightSpecular); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glMaterialfv(GL_FRONT, GL_SPECULAR,lightSpecular); glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, materialColor); glMateriali(GL_FRONT, GL_SHININESS,128); } // Move the cube slightly forward and to the left glTranslatef(-10.0f, 0.0f, 10.0f); switch(nStep) { // Just draw the wire framed cube case 0: glutWireCube(50.0f); break; // Same wire cube with hidden line removal simulated case 1: // Front Face (before rotation) glBegin(GL_LINES); glVertex3f(25.0f,25.0f,25.0f); glVertex3f(25.0f,-25.0f,25.0f); glVertex3f(25.0f,-25.0f,25.0f); glVertex3f(-25.0f,-25.0f,25.0f); glVertex3f(-25.0f,-25.0f,25.0f); glVertex3f(-25.0f,25.0f,25.0f); glVertex3f(-25.0f,25.0f,25.0f); glVertex3f(25.0f,25.0f,25.0f); glEnd(); // Top of cube glBegin(GL_LINES); // Front Face glVertex3f(25.0f,25.0f,25.0f); glVertex3f(25.0f,25.0f,-25.0f); glVertex3f(25.0f,25.0f,-25.0f); glVertex3f(-25.0f,25.0f,-25.0f); glVertex3f(-25.0f,25.0f,-25.0f); glVertex3f(-25.0f,25.0f,25.0f); glVertex3f(-25.0f,25.0f,25.0f); glVertex3f(25.0f,25.0f,25.0f); glEnd(); // Last two segments for effect glBegin(GL_LINES); glVertex3f(25.0f,25.0f,-25.0f); glVertex3f(25.0f,-25.0f,-25.0f); glVertex3f(25.0f,-25.0f,-25.0f); glVertex3f(25.0f,-25.0f,25.0f); glEnd(); break; // Uniform colored surface, looks 2D and goofey case 2: glutSolidCube(50.0f); break; case 3: glutSolidCube(50.0f); break; // Draw a shadow with some lighting case 4: glGetFloatv(GL_MODELVIEW_MATRIX, (GLfloat *) cubeXform); glutSolidCube(50.0f); glPopMatrix(); // Disable lighting, we'll just draw the shadow as black glDisable(GL_LIGHTING); glPushMatrix(); MakeShadowMatrix(ground, lightpos, cubeXform); glMultMatrixf((GLfloat *)cubeXform); glTranslatef(-10.0f, 0.0f, 10.0f); // Set drawing color to Black glColor3f(0.0f, 0.0f, 0.0f); glutSolidCube(50.0f); break; case 5: glColor3ub(255,255,255); glGetFloatv(GL_MODELVIEW_MATRIX, (GLfloat *) cubeXform); // Front Face (before rotation) glBindTexture(GL_TEXTURE_2D, textures[1]); glBegin(GL_QUADS); glTexCoord2f(1.0f, 1.0f); glVertex3f(25.0f,25.0f,25.0f); glTexCoord2f(1.0f, 0.0f); glVertex3f(25.0f,-25.0f,25.0f); glTexCoord2f(0.0f, 0.0f); glVertex3f(-25.0f,-25.0f,25.0f); glTexCoord2f(0.0f, 1.0f); glVertex3