// SphereWorld.cpp
// OpenGL SuperBible
// New and improved (performance) sphere world
// Program by Richard S. Wright Jr.
#include <GLTools.h>
#include <GLShaderManager.h>
#include <GLFrustum.h>
#include <GLBatch.h>
#include <GLFrame.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
GLShaderManager shaderManager; // Shader Manager
GLMatrixStack modelViewMatrix; // Modelview Matrix
GLMatrixStack projectionMatrix; // Projection Matrix
GLFrustum viewFrustum; // View Frustum
GLGeometryTransform transformPipeline; // Geometry Transform Pipeline
GLTriangleBatch torusBatch;
GLBatch floorBatch;
GLTriangleBatch sphereBatch;
GLFrame cameraFrame;
//////////////////////////////////////////////////////////////////
// This function does any needed initialization on the rendering
// context.
void SetupRC()
{
// Initialze Shader Manager
shaderManager.InitializeStockShaders();
glEnable(GL_DEPTH_TEST);
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
// This makes a torus
gltMakeTorus(torusBatch, 0.4f, 0.15f, 30, 30);
// This make a sphere
gltMakeSphere(sphereBatch, 0.1f, 26, 13);
floorBatch.Begin(GL_LINES, 324);
for (GLfloat x = -20.0; x <= 20.0f; x += 0.5) {
floorBatch.Vertex3f(x, -0.55f, 20.0f);
floorBatch.Vertex3f(x, -0.55f, -20.0f);
floorBatch.Vertex3f(20.0f, -0.55f, x);
floorBatch.Vertex3f(-20.0f, -0.55f, x);
}
floorBatch.End();
}
///////////////////////////////////////////////////
// Screen changes size or is initialized
void ChangeSize(int nWidth, int nHeight)
{
glViewport(0, 0, nWidth, nHeight);
// Create the projection matrix, and load it on the projection matrix stack
viewFrustum.SetPerspective(35.0f, float(nWidth) / float(nHeight), 1.0f, 100.0f);
projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix());
// Set the transformation pipeline to use the two matrix stacks
transformPipeline.SetMatrixStacks(modelViewMatrix, projectionMatrix);
}
// 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);
}
// Called to draw scene
void RenderScene(void)
{
// Color values
static GLfloat vFloorColor[] = { 0.0f, 1.0f, 0.0f, 1.0f };
static GLfloat vTorusColor[] = { 1.0f, 0.0f, 0.0f, 1.0f };
static GLfloat vSphereColor[] = { 0.0f, 0.0f, 1.0f, 1.0f };
// Time Based animation
static CStopWatch rotTimer;
float yRot = rotTimer.GetElapsedSeconds() * 60.0f;
// Clear the color and depth buffers
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/*
Stack:modelViewMatrix
*/
// Save the current modelview matrix (the identity matrix)
modelViewMatrix.PushMatrix();
/*
Stack:
top:modelViewMatrix
modelViewMatrix
*/
M3DMatrix44f mCamera;
cameraFrame.GetCameraMatrix(mCamera);//设置摄像机视口矩阵
modelViewMatrix.PushMatrix(mCamera);//模型视图矩阵关联摄像机矩阵
// Draw the ground
shaderManager.UseStockShader(GLT_SHADER_FLAT,
transformPipeline.GetModelViewProjectionMatrix(),
vFloorColor);
floorBatch.Draw();
// Draw the spinning Torus
modelViewMatrix.Translate(0.0f, 0.0f, -2.5f);//模型视图矩阵向后平移
/*
Stack:
top:modelViewMatrix + Z轴平移-2.5f
modelViewMatrix
modelViewMatrix
*/
// Save the Translation
modelViewMatrix.PushMatrix();
/*
Stack:
top:modelViewMatrix + Z轴平移-2.5f + 绕Y轴旋转
modelViewMatrix
modelViewMatrix
*/
// Apply a rotation and draw the torus
modelViewMatrix.Rotate(yRot, 0.0f, 1.0f, 0.0f);//绕着y轴旋转
shaderManager.UseStockShader(GLT_SHADER_FLAT, transformPipeline.GetModelViewProjectionMatrix(),
vTorusColor);
torusBatch.Draw();
/*
Stack:
top:modelViewMatrix
modelViewMatrix
*/
modelViewMatrix.PopMatrix(); // "Erase" the Rotation from before
/*
Stack:
top:modelViewMatrix + 绕Y轴旋转 + 平移0.8
modelViewMatrix
*/
// Apply another rotation, followed by a translation, then draw the sphere
modelViewMatrix.Rotate(yRot * -2.0f, 0.0f, 0.1f, 0.0f);//绕着y轴旋转并平移,原点为(0,0,0)
//如果把旋转放到平移的后面(下面)执行,将绕着Y轴旋转,原点为(0,8,0,0)
modelViewMatrix.Translate(0.8f, 0.0f, 0.0f);//浮点数指的是比例
shaderManager.UseStockShader(GLT_SHADER_FLAT, transformPipeline.GetModelViewProjectionMatrix(),
vSphereColor);
sphereBatch.Draw();
// Restore the previous modleview matrix (the identity matrix)
/*
Stack:
top:modelViewMatrix
*/
modelViewMatrix.PopMatrix();
/*
Stack:
top:(其他)
*/
modelViewMatrix.PopMatrix();
// Do the buffer Swap
glutSwapBuffers();
// Tell GLUT to do it again
glutPostRedisplay();
}
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");
glutSpecialFunc(SpecialKeys);
glutReshapeFunc(ChangeSize);
glutDisplayFunc(RenderScene);
GLenum err = glewInit();
if (GLEW_OK != err) {
fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));
return 1;
}
SetupRC();
glutMainLoop();
return 0;
}
OpenGL 入门教程(六) 旋转加平移
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转载自blog.csdn.net/a1317338022/article/details/78742816
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