球体世界:
地面效果是先渲染了反转的场景,然后再上面渲染大理石地板,并用一个Alpha值与背景进行混合,然后再渲染正常的场景达到了这种效果。新的内容在LoadTGA函数,内部格式参数用了通用压缩纹理格式GL_COMPRESSED_RGB 即glTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB, nWidth, nHeight, 0, eFormat, GL_UNSIGNED_BYTE, pBits); 其他代码都是我们已经学过的内容。
// SphereWorld.cpp
// OpenGL SuperBible
// New and improved (performance) sphere world
// Program by Richard S. Wright Jr.
#pragma comment(lib, "gltools.lib")
#include <GLTools.h>
#include <GLShaderManager.h>
#include <GLFrustum.h>
#include <GLBatch.h>
#include <GLMatrixStack.h>
#include <GLGeometryTransform.h>
#include <StopWatch.h>
#include <math.h>
#include <stdio.h>
#ifdef __APPLE__
#include <glut/glut.h>
#else
#define FREEGLUT_STATIC
#include <GL/glut.h>
#endif
#define NUM_SPHERES 50
GLFrame spheres[NUM_SPHERES];
GLShaderManager shaderManager; // Shader Manager
GLMatrixStack modelViewMatrix; // Modelview Matrix
GLMatrixStack projectionMatrix; // Projection Matrix
GLFrustum viewFrustum; // View Frustum
GLGeometryTransform transformPipeline; // Geometry Transform Pipeline
GLFrame cameraFrame; // Camera frame
GLTriangleBatch torusBatch;
GLTriangleBatch sphereBatch;
GLBatch floorBatch;
GLuint uiTextures[3];
void DrawSongAndDance(GLfloat yRot) // Called to draw dancing objects
{
static GLfloat vWhite[] = { 1.0f, 1.0f, 1.0f, 1.0f };
static GLfloat vLightPos[] = { 0.0f, 3.0f, 0.0f, 1.0f };
// Get the light position in eye space
M3DVector4f vLightTransformed;
M3DMatrix44f mCamera;
modelViewMatrix.GetMatrix(mCamera);
m3dTransformVector4(vLightTransformed, vLightPos, mCamera);
// Draw the light source
modelViewMatrix.PushMatrix();
modelViewMatrix.Translatev(vLightPos);
shaderManager.UseStockShader(GLT_SHADER_FLAT,
transformPipeline.GetModelViewProjectionMatrix(),
vWhite);
sphereBatch.Draw();
modelViewMatrix.PopMatrix();
glBindTexture(GL_TEXTURE_2D, uiTextures[2]);
for (int i = 0; i < NUM_SPHERES; i++) {
modelViewMatrix.PushMatrix();
modelViewMatrix.MultMatrix(spheres[i]);
shaderManager.UseStockShader(GLT_SHADER_TEXTURE_POINT_LIGHT_DIFF,
modelViewMatrix.GetMatrix(),
transformPipeline.GetProjectionMatrix(),
vLightTransformed,
vWhite,
0);
sphereBatch.Draw();
modelViewMatrix.PopMatrix();
}
// Song and dance
modelViewMatrix.Translate(0.0f, 0.2f, -2.5f);
modelViewMatrix.PushMatrix(); // Saves the translated origin
modelViewMatrix.Rotate(yRot, 0.0f, 1.0f, 0.0f);
// Draw stuff relative to the camera
glBindTexture(GL_TEXTURE_2D, uiTextures[1]);
shaderManager.UseStockShader(GLT_SHADER_TEXTURE_POINT_LIGHT_DIFF,
modelViewMatrix.GetMatrix(),
transformPipeline.GetProjectionMatrix(),
vLightTransformed,
vWhite,
0);
torusBatch.Draw();
modelViewMatrix.PopMatrix(); // Erased the rotate
modelViewMatrix.Rotate(yRot * -2.0f, 0.0f, 1.0f, 0.0f);
modelViewMatrix.Translate(0.8f, 0.0f, 0.0f);
glBindTexture(GL_TEXTURE_2D, uiTextures[2]);
shaderManager.UseStockShader(GLT_SHADER_TEXTURE_POINT_LIGHT_DIFF,
modelViewMatrix.GetMatrix(),
transformPipeline.GetProjectionMatrix(),
vLightTransformed,
vWhite,
0);
sphereBatch.Draw();
}
bool LoadTGATexture(const char *szFileName, GLenum minFilter, GLenum magFilter, GLenum wrapMode)
{
GLbyte *pBits;
int nWidth, nHeight, nComponents;
GLenum eFormat;
// Read the texture bits
pBits = gltReadTGABits(szFileName, &nWidth, &nHeight, &nComponents, &eFormat);
if (pBits == NULL)
return false;
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrapMode);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrapMode);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, minFilter);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, magFilter);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB, nWidth, nHeight, 0,
eFormat, GL_UNSIGNED_BYTE, pBits);
free(pBits);
if (minFilter == GL_LINEAR_MIPMAP_LINEAR ||
minFilter == GL_LINEAR_MIPMAP_NEAREST ||
minFilter == GL_NEAREST_MIPMAP_LINEAR ||
minFilter == GL_NEAREST_MIPMAP_NEAREST)
glGenerateMipmap(GL_TEXTURE_2D);
return true;
}
//
// This function does any needed initialization on the rendering
// context.
void SetupRC()
{
// Make sure OpenGL entry points are set
glewInit();
// Initialze Shader Manager
shaderManager.InitializeStockShaders();
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
// This makes a torus
gltMakeTorus(torusBatch, 0.4f, 0.15f, 40, 20);
// This makes a sphere
gltMakeSphere(sphereBatch, 0.1f, 26, 13);
// Make the solid ground
GLfloat texSize = 10.0f;
floorBatch.Begin(GL_TRIANGLE_FAN, 4, 1);
floorBatch.MultiTexCoord2f(0, 0.0f, 0.0f);
floorBatch.Vertex3f(-20.0f, -0.41f, 20.0f);
floorBatch.MultiTexCoord2f(0, texSize, 0.0f);
floorBatch.Vertex3f(20.0f, -0.41f, 20.0f);
floorBatch.MultiTexCoord2f(0, texSize, texSize);
floorBatch.Vertex3f(20.0f, -0.41f, -20.0f);
floorBatch.MultiTexCoord2f(0, 0.0f, texSize);
floorBatch.Vertex3f(-20.0f, -0.41f, -20.0f);
floorBatch.End();
// Make 3 texture objects
glGenTextures(3, uiTextures);
// Load the Marble
glBindTexture(GL_TEXTURE_2D, uiTextures[0]);
LoadTGATexture("marble.tga", GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR, GL_REPEAT);
// Load Mars
glBindTexture(GL_TEXTURE_2D, uiTextures[1]);
LoadTGATexture("marslike.tga", GL_LINEAR_MIPMAP_LINEAR,
GL_LINEAR, GL_CLAMP_TO_EDGE);
// Load Moon
glBindTexture(GL_TEXTURE_2D, uiTextures[2]);
LoadTGATexture("moonlike.tga", GL_LINEAR_MIPMAP_LINEAR,
GL_LINEAR, GL_CLAMP_TO_EDGE);
// Randomly place the spheres
for (int i = 0; i < NUM_SPHERES; i++) {
GLfloat x = ((GLfloat)((rand() % 400) - 200) * 0.1f);
GLfloat z = ((GLfloat)((rand() % 400) - 200) * 0.1f);
spheres[i].SetOrigin(x, 0.0f, z);
}
}
// Do shutdown for the rendering context
void ShutdownRC(void)
{
glDeleteTextures(3, uiTextures);
}
// Called to draw scene
void RenderScene(void)
{
static CStopWatch rotTimer;
float yRot = rotTimer.GetElapsedSeconds() * 60.0f;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
modelViewMatrix.PushMatrix();
M3DMatrix44f mCamera;
cameraFrame.GetCameraMatrix(mCamera);
modelViewMatrix.MultMatrix(mCamera);
// Draw the world upside down
modelViewMatrix.PushMatrix();
modelViewMatrix.Scale(1.0f, -1.0f, 1.0f); // Flips the Y Axis
modelViewMatrix.Translate(0.0f, 0.8f, 0.0f); // Scootch the world down a bit...
glFrontFace(GL_CW);
DrawSongAndDance(yRot);
glFrontFace(GL_CCW);
modelViewMatrix.PopMatrix();
// Draw the solid ground
glEnable(GL_BLEND);
glBindTexture(GL_TEXTURE_2D, uiTextures[0]);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
static GLfloat vFloorColor[] = { 1.0f, 1.0f, 1.0f, 0.75f };
shaderManager.UseStockShader(GLT_SHADER_TEXTURE_MODULATE,
transformPipeline.GetModelViewProjectionMatrix(),
vFloorColor,
0);
floorBatch.Draw();
glDisable(GL_BLEND);
DrawSongAndDance(yRot);
modelViewMatrix.PopMatrix();
// Do the buffer Swap
glutSwapBuffers();
// Do it again
glutPostRedisplay();
}
// Respond to arrow keys by moving the camera frame of reference
void SpecialKeys(int key, int x, int y)
{
float linear = 0.1f;
float angular = float(m3dDegToRad(5.0f));
if (key == GLUT_KEY_UP)
cameraFrame.MoveForward(linear);
if (key == GLUT_KEY_DOWN)
cameraFrame.MoveForward(-linear);
if (key == GLUT_KEY_LEFT)
cameraFrame.RotateWorld(angular, 0.0f, 1.0f, 0.0f);
if (key == GLUT_KEY_RIGHT)
cameraFrame.RotateWorld(-angular, 0.0f, 1.0f, 0.0f);
}
void ChangeSize(int nWidth, int nHeight)
{
glViewport(0, 0, nWidth, nHeight);
transformPipeline.SetMatrixStacks(modelViewMatrix, projectionMatrix);
viewFrustum.SetPerspective(35.0f, float(nWidth) / float(nHeight), 1.0f, 100.0f);
projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix());
modelViewMatrix.LoadIdentity();
}
int main(int argc, char* argv[])
{
gltSetWorkingDirectory(argv[0]);
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(800, 600);
glutCreateWindow("OpenGL SphereWorld");
glutReshapeFunc(ChangeSize);
glutDisplayFunc(RenderScene);
glutSpecialFunc(SpecialKeys);
SetupRC();
glutMainLoop();
ShutdownRC();
return 0;
}