[英]How do I get OpenGL/GLUT working with Eclipse IDE (cocoa 64 bit) using C++ and on Snow Leopard
[英]How do I get color to change using glut and openGL?
我試圖教自己在沒有用戶輸入的情況下為一個對象設置動畫,到目前為止我已經想出了如何使一個場景旋轉。 如何讓對象改變顏色? 我認為我的代碼會做到,但它仍然是一個白色三角形(甚至不是一個不同的顏色)。
如何在三角形或透視圖旋轉的同時更改顏色?
這是我目前的代碼:
#include <GL/glut.h>
float color1;
float color2;
float color3;
void changeSize(int w, int h) {
// Prevent a divide by zero, when window is too short
// (you cant make a window of zero width).
if (h == 0)
h = 1;
float ratio = w * 1.0 / h;
// Use the Projection Matrix
glMatrixMode(GL_PROJECTION);
// Reset Matrix
glLoadIdentity();
// Set the viewport to be the entire window
glViewport(0, 0, w, h);
// Set the correct perspective.
gluPerspective(45.0f, ratio, 0.1f, 100.0f);
//changeColor?
color1 += 0.1f;
color2 += 0.3;
color3 += color2;
if (color1 > 1.0)
color1 = 0;
if (color2 > 1.0)
color2 = 0;
if (color3 > 1.0)
color3 = 0;
// Get Back to the Modelview
glMatrixMode(GL_MODELVIEW);
}
float angle = 0.0f;
void renderScene(void) {
// Clear Color and Depth Buffers
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Reset transformations
glLoadIdentity();
// Set the camera
gluLookAt(0.0f, 0.0f, 10.0f,
0.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f);
glRotatef(angle, 0.0f, 1.0f, 0.0f);
glBegin(GL_TRIANGLES);
glColor3f(color1, color2, color3);
glVertex3f(2.0f, -2.0f, 0.0f);
glVertex3f(2.0f, 0.0f, 0.0);
glVertex3f(0.0f, 2.0f, 0.0);
glEnd();
angle += 0.1f;
color1 += 0.1f;
color2 += 0.3;
color3 += color2;
glutSwapBuffers();
}
int main(int argc, char **argv) {
// init GLUT and create window
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowPosition(100, 100);
glutInitWindowSize(320, 320);
glutCreateWindow("tutorial example");
// register callbacks
glutDisplayFunc(renderScene);
glutReshapeFunc(changeSize);
glutIdleFunc(renderScene);
// enter GLUT event processing cycle
glutMainLoop();
return 1;
}
浮點顏色必須在[0,1]的范圍內,你只需要在你的值上添加一些東西,而不要將它重置為零,所以它在前10幀中變得大於1(=非常快),OpenGL將它固定為1,所以你看到它是白色的。
也就是說, changeSize
中的一堆if
應該實際上在renderScene
。
glutTimerFunc()
回調 glutDisplayFunc()
回調重新設置投影/模型視圖矩陣,有助於防止奇怪的矩陣問題 全部一起:
#include <GL/glut.h>
float angle = 0.0f;
float color1 = 0.0f;
float color2 = 0.0f;
float color3 = 0.0f;
void timer( int value )
{
angle += 3.0f;
//changeColor?
color1 += 0.001f;
color2 += 0.003f;
color3 += color2;
if (color1 > 1.0)
color1 = 0;
if (color2 > 1.0)
color2 = 0;
if (color3 > 1.0)
color3 = 0;
glutPostRedisplay();
glutTimerFunc( 16, timer, 0 );
}
void renderScene()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
double w = glutGet( GLUT_WINDOW_WIDTH );
double h = glutGet( GLUT_WINDOW_HEIGHT );
gluPerspective(45.0f, w / h, 0.1f, 100.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt
(
0.0f, 0.0f, 10.0f,
0.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f
);
glRotatef(angle, 0.0f, 1.0f, 0.0f);
glBegin(GL_TRIANGLES);
glColor3f(color1, color2, color3);
glVertex3f(2.0f, -2.0f, 0.0f);
glVertex3f(2.0f, 0.0f, 0.0);
glVertex3f(0.0f, 2.0f, 0.0);
glEnd();
glutSwapBuffers();
}
int main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowSize(320, 320);
glutCreateWindow("tutorial example");
glutDisplayFunc(renderScene);
glutTimerFunc( 0, timer, 0 );
glutMainLoop();
return 1;
}
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