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| #include <math.h>
#include <GL/glew.h>
#include <GL/freeglut.h>
#define M_PI 3.141592f
#define BUFFER_OFFSET(offset) ((GLvoid *) NULL + offset)
#define NumberOf(array) (sizeof(array)/sizeof(array[0]))
typedef struct
{
GLfloat x, y, z;
} vec3;
typedef struct
{
vec3 xlate; // Translation
GLfloat angle;
vec3 axis;
} XForm;
enum {Cube, Cone, NumVAOs};
GLuint VAO[NumVAOs];
GLenum PrimType[NumVAOs];
GLsizei NumElements[NumVAOs];
XForm Xform[NumVAOs] =
{
{ {-2.0, 0.0, 0.0}, 0.0, {0.0, 1.0, 0.0} },
{ { 0.0, 0.0, 2.0}, 0.0, {1.0, 0.0, 0.0} }
};
GLfloat Angle = 0.0;
void Init(void)
{
enum { Vertices, Colors, Elements, NumVBOs };
GLuint buffers[NumVBOs];
glClearColor( 0.0, 0.0, 0.0, 0.0);
glGenVertexArrays(NumVAOs, VAO);
{
GLfloat cubeVerts[][3] =
{
{-1.0,-1.0,-1.0},
{-1.0,-1.0, 1.0},
{-1.0, 1.0,-1.0},
{-1.0, 1.0, 1.0},
{ 1.0,-1.0,-1.0},
{ 1.0,-1.0, 1.0},
{ 1.0, 1.0,-1.0},
{ 1.0, 1.0, 1.0}
};
GLfloat cubeColors[][3] =
{
{ 0.0, 0.0, 1.0},
{ 0.0, 0.0, 1.0},
{ 0.0, 1.0, 0.0},
{ 0.0, 1.0, 1.0},
{ 1.0, 0.0, 0.0},
{ 1.0, 0.0, 1.0},
{ 1.0, 1.0, 0.0},
{ 1.0, 1.0, 1.0}
};
GLfloat cubeIndices[] =
{
0,1,3,2,
4,6,7,5,
2,3,7,6,
0,4,5,1,
0,2,6,4,
1,5,7,3
};
glBindVertexArray(VAO[Cube]);
glGenBuffers(NumVBOs, buffers);
glBindBuffer(GL_ARRAY_BUFFER, buffers[Vertices]);
glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVerts),
cubeVerts,GL_STATIC_DRAW);
glVertexPointer(3,GL_FLOAT,0,BUFFER_OFFSET(0));
glEnableClientState(GL_VERTEX_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER,buffers[Colors]);
glBufferData(GL_ARRAY_BUFFER,sizeof(cubeColors),
cubeColors,GL_STATIC_DRAW);
glColorPointer(3,GL_FLOAT,0,BUFFER_OFFSET(0));
glEnableClientState(GL_COLOR_ARRAY);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[Elements]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(cubeIndices),
cubeIndices,GL_STATIC_DRAW);
PrimType[Cube] = GL_QUADS;
NumElements[Cube] = NumberOf(cubeIndices);
}
{
float dTheta;
#define NumConePoints 36
// We add one more vertex for the cone's apex
GLfloat coneVerts[NumConePoints+1][3] =
{
{0.0, 0.0, 1.0}
};
GLfloat coneColors[NumConePoints+1][3] =
{
{1.0, 1.0, 1.0}
};
GLfloat coneIndices[NumConePoints+1];
dTheta = 2*M_PI / (NumConePoints - 1);
for (int i = 0, idx=1; i < NumConePoints; ++i, ++idx)
{
float theta = i*dTheta;
coneVerts[idx][0] = cos(theta);
coneVerts[idx][1] = sin(theta);
coneVerts[idx][2] = 0.0;
coneColors[idx][0] = cos(theta);
coneColors[idx][1] = sin(theta);
coneColors[idx][2] = 0.0;
coneIndices[idx] = idx;
}
glBindVertexArray(VAO[Cone]);
glGenBuffers(NumVBOs, buffers);
glBindBuffer(GL_ARRAY_BUFFER, buffers[Vertices]);
glBufferData(GL_ARRAY_BUFFER, sizeof(coneVerts),
coneVerts, GL_STATIC_DRAW);
glVertexPointer(3, GL_FLOAT, 0, BUFFER_OFFSET(0));
glEnableClientState(GL_VERTEX_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER, buffers[Colors]);
glBufferData(GL_ARRAY_BUFFER, sizeof(coneColors),
coneColors, GL_STATIC_DRAW);
glColorPointer(3, GL_FLOAT, 0, BUFFER_OFFSET(0));
glEnableClientState(GL_COLOR_ARRAY);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[Elements]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(coneIndices),
coneIndices,GL_STATIC_DRAW);
PrimType[Cone] = GL_TRIANGLE_FAN;
NumElements[Cone] = NumberOf(coneIndices);
}
glEnable(GL_DEPTH_TEST);
glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
}
void Display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotatef(Angle, 0.0, 1.0, 0.0);
for (int i = 0; i < NumVAOs; ++i)
{
glPushMatrix();
glTranslatef(Xform[i].xlate.x, Xform[i].xlate.y,
Xform[i].xlate.z);
glRotatef(Xform[i].angle, Xform[i].axis.x, Xform[i].axis.y,
Xform[i].axis.z);
glBindVertexArray(VAO[i]);
glDrawElements(PrimType[i], NumElements[i],
GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
glPopMatrix();
}
/*
glTranslatef( 0.0, 0.0,-5.0);
glutWireCube(1.0);
*/
glPopMatrix();
//glutSwapBuffers();
}
void Reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(60.0, 1.0, 1.0, 100.0);
glMatrixMode(GL_MODELVIEW);
}
int main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize(500, 500);
glutInitWindowPosition(100, 100);
glutCreateWindow(argv[0]);
GLenum err = glewInit();
if (GLEW_OK != err)
{
/* Problem: glewInit failed, something is seriously wrong. */
return 1;
}
if (!GLEW_VERSION_3_3)
{
/* OpenGL 3.3 not supported */
return 1;
}
glutInitContextVersion(3,3);
glutInitContextFlags(GLUT_FORWARD_COMPATIBLE);
Init();
glutDisplayFunc(Display);
glutReshapeFunc(Reshape);
glutMainLoop();
return 0;
} |
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