GLSL Tessellation Shader简单示例

#include<windows.h> #include<stdio.h> #include <stdlib.h> #include <gl/glew.h> #include <gl/glut.h> #include "textfile.h" #include "debugInfo.h" #define MIN_INSERTION 2 #define MAX_INSERTION 16 bool shader_flag = false; float eye[] = {0.0, 0.0, 8.0}; float center[] = {0.0, 0.0, 0.0}; int left_click = GLUT_UP; int xold; int yold; float rotation_x = 0; float rotation_y = 0; int wHeight = 0; int wWidth = 0; GLuint vertex_shader; GLuint fragment_shader; GLuint tcs_shader; GLuint tes_shader; GLuint shader_program; GLuint vertex_buffer; GLuint lineIndexBuffer; GLuint vao; GLfloat vertices[] = {2,2,0, -2,2,0, -2,-2,0, 2,-2,0}; GLuint line_index[] = {0,1, 1,2, 2,3, 3,0}; float model_view_matrix[16]; float projection_matrix[16]; int edge_insertion_num = 2; int face_insertion_num = 2; void DrawScene() { glEnableVertexAttribArray(0); glBindVertexArray(vao); glVertexAttribPointer(0,3,GL_FLOAT,GL_TRUE,0,0); if(shader_flag) { glPatchParameteri(GL_PATCH_VERTICES,4); glDrawArrays(GL_PATCHES, 0,4); } else { glDrawArrays(GL_LINES, 0,4); } glBindVertexArray(0); glDisableVertexAttribArray(0); } void redraw() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); gluLookAt(eye[0], eye[1], eye[2], center[0], center[1], center[2], 0, 1, 0); //glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); glEnable(GL_DEPTH_TEST); glEnable(GL_LIGHTING); GLfloat white[] = { 1.0, 1.0, 1.0, 1.0 }; GLfloat light_pos[] = {5,5,5,1}; glLightfv(GL_LIGHT0, GL_POSITION, light_pos); glLightfv(GL_LIGHT0, GL_AMBIENT, white); glEnable(GL_LIGHT0); glRotatef(rotation_y, 1, 0, 0); glRotatef(rotation_x, 0, 1, 0); if(shader_flag) { glUseProgram(shader_program); glGetFloatv(GL_MODELVIEW_MATRIX,model_view_matrix); glGetFloatv(GL_PROJECTION_MATRIX,projection_matrix); glUniformMatrix4fv(glGetUniformLocation(shader_program,"ModelViewMatrix"),1,GL_FALSE,model_view_matrix); glUniformMatrix4fv(glGetUniformLocation(shader_program,"ProjectionMatrix"),1,GL_FALSE,projection_matrix); glUniform1i(glGetUniformLocation(shader_program,"edge_tess_num"),edge_insertion_num); glUniform1i(glGetUniformLocation(shader_program,"face_tess_num"),face_insertion_num); } else { glUseProgram(0); } DrawScene(); glutSwapBuffers(); } void updateView(int width, int height) { glViewport(0,0,width,height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); float whRatio = (GLfloat)width/(GLfloat)height; gluPerspective(45.0f, whRatio,0.1f,100.0f); glMatrixMode(GL_MODELVIEW); } void reshape(int width, int height) { if (height==0) { height=1; } wHeight = height; wWidth = width; updateView(wHeight, wWidth); } void idle() { glutPostRedisplay(); } void key(unsigned char k, int x, int y) { switch(k) { case 27: { exit(0); } case 's': { shader_flag = !shader_flag; break; } case 'i': { edge_insertion_num = (edge_insertion_num<=MIN_INSERTION)?MIN_INSERTION:edge_insertion_num-1; break; } case 'o': { edge_insertion_num = (edge_insertion_num>=MAX_INSERTION)?MAX_INSERTION:edge_insertion_num+1; break; } case 'k': { face_insertion_num = (face_insertion_num<=MIN_INSERTION)?MIN_INSERTION:face_insertion_num-1; break; } case 'l': { face_insertion_num = (face_insertion_num>=MAX_INSERTION)?MAX_INSERTION:face_insertion_num+1; break; } } } void MouseFunc(int button, int state, int x, int y) { if (GLUT_LEFT_BUTTON == button) { left_click = state; } xold = x; yold = y; } void MotionFunc(int x, int y) { if (GLUT_DOWN == left_click) { rotation_y = rotation_y + (y - yold) / 3.0; rotation_x = rotation_x + (x - xold) / 3.0; if (rotation_y > 90) { rotation_y = 90; } if (rotation_y < -90) { rotation_y = -90; } glutPostRedisplay (); } xold = x; yold = y; } void setShader() { char *vs_edge = NULL; char *fs_edge = NULL; char *tcs_edge = NULL; char *tes_edge =NULL; vertex_shader = glCreateShader(GL_VERTEX_SHADER); fragment_shader = glCreateShader(GL_FRAGMENT_SHADER); tcs_shader = glCreateShader(GL_TESS_CONTROL_SHADER); tes_shader = glCreateShader(GL_TESS_EVALUATION_SHADER); vs_edge = textFileRead("edge.vert"); fs_edge = textFileRead("edge.frag"); tcs_edge = textFileRead("edge.tcs"); tes_edge = textFileRead("edge.tes"); const char * vs = vs_edge; const char * fs = fs_edge; const char * tcs = tcs_edge; const char * tes = tes_edge; glShaderSource(vertex_shader, 1, &vs,NULL); glShaderSource(fragment_shader, 1, &fs,NULL); glShaderSource(tcs_shader,1,&tcs,NULL); glShaderSource(tes_shader,1,&tes,NULL); free(vs_edge); free(fs_edge); free(tcs_edge); free(tes_edge); glCompileShader(vertex_shader); glCompileShader(fragment_shader); glCompileShader(tcs_shader); glCompileShader(tes_shader); shader_program = glCreateProgram(); glAttachShader(shader_program,vertex_shader); glAttachShader(shader_program,fragment_shader); glAttachShader(shader_program,tcs_shader); glAttachShader(shader_program,tes_shader); glLinkProgram(shader_program); printf("vert:\n"); printShaderInfoLog(vertex_shader); printf("\nfrag:\n"); printShaderInfoLog(fragment_shader); printf("\ntcs:\n"); printShaderInfoLog(tcs_shader); printf("\ntes:\n"); printShaderInfoLog(tes_shader); } void init() { setShader(); glGenVertexArrays(1, &vao); glBindVertexArray(vao); glGenBuffers(1, &vertex_buffer); glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); glBufferData(GL_ARRAY_BUFFER,100,vertices,GL_STATIC_DRAW); glGenBuffers(1, &lineIndexBuffer); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, lineIndexBuffer); glBufferData(GL_ELEMENT_ARRAY_BUFFER, 100, line_index, GL_STATIC_DRAW); } int main (int argc, char *argv[]) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE); glutInitWindowSize(480,480); glutCreateWindow("Tess"); glutDisplayFunc(redraw); glutReshapeFunc(reshape); glutKeyboardFunc(key); glutIdleFunc(idle); glutMouseFunc(MouseFunc); glutMotionFunc(MotionFunc); glewInit(); if (glewIsSupported("GL_VERSION_4_0")) { printf("Ready for OpenGL 2.0\n"); } else { printf("OpenGL 2.0 not supported\n"); exit(1); } init(); glutMainLoop(); return 0; }