전체코드
#include <sb7.h>
// Undefine this to take color from screen space
#define INTERPOLATE_COLOR
class colorfromposition_app : public sb7::application
{
void init()
{
static const char title[] = "OpenGL SuperBible - Simple Triangle";
sb7::application::init();
memcpy(info.title, title, sizeof(title));
}
virtual void startup()
{
#ifndef INTERPOLATE_COLOR
static const char * vs_source[] =
{
"#version 420 core \n"
" \n"
"void main(void) \n"
"{ \n"
" const vec4 vertices[] = vec4[](vec4( 0.25, -0.25, 0.5, 1.0), \n"
" vec4(-0.25, -0.25, 0.5, 1.0), \n"
" vec4( 0.25, 0.25, 0.5, 1.0)); \n"
" \n"
" gl_Position = vertices[gl_VertexID]; \n"
"} \n"
};
static const char * fs_source[] =
{
"#version 420 core \n"
" \n"
"out vec4 color; \n"
" \n"
"void main(void) \n"
"{ \n"
" color = vec4(sin(gl_FragCoord.x * 0.25) * 0.5 + 0.5, \n"
" cos(gl_FragCoord.y * 0.25) * 0.5 + 0.5, \n"
" sin(gl_FragCoord.x * 0.15) * cos(gl_FragCoord.y * 0.1), \n"
" 1.0); \n"
"} \n"
};
#else
static const char * vs_source[] =
{
"#version 420 core \n"
" \n"
"out vec4 vs_color; \n"
"void main(void) \n"
"{ \n"
" const vec4 vertices[] = vec4[](vec4( 0.25, -0.25, 0.5, 1.0), \n"
" vec4(-0.25, -0.25, 0.5, 1.0), \n"
" vec4( 0.25, 0.25, 0.5, 1.0)); \n"
" const vec4 colors[] = vec4[](vec4(1.0, 0.0, 0.0, 1.0), \n"
" vec4(0.0, 1.0, 0.0, 1.0), \n"
" vec4(0.0, 0.0, 1.0, 1.0)); \n"
" \n"
" gl_Position = vertices[gl_VertexID]; \n"
" vs_color = colors[gl_VertexID]; \n"
"} \n"
};
static const char * fs_source[] =
{
"#version 420 core \n"
" \n"
"in vec4 vs_color; \n"
"out vec4 color; \n"
" \n"
"void main(void) \n"
"{ \n"
" color = vs_color; \n"
"} \n"
};
#endif
program = glCreateProgram();
GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fs, 1, fs_source, NULL);
glCompileShader(fs);
GLuint vs = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vs, 1, vs_source, NULL);
glCompileShader(vs);
glAttachShader(program, vs);
glAttachShader(program, fs);
glLinkProgram(program);
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
}
virtual void render(double currentTime)
{
static const GLfloat green[] = { 0.0f, 0.25f, 0.0f, 1.0f };
glClearBufferfv(GL_COLOR, 0, green);
glUseProgram(program);
glDrawArrays(GL_TRIANGLES, 0, 3);
}
virtual void shutdown()
{
glDeleteVertexArrays(1, &vao);
glDeleteProgram(program);
}
private:
GLuint program;
GLuint vao;
};
DECLARE_MAIN(colorfromposition_app)
설명
static const char * vs_source[] =
{
"#version 420 core \n"
" \n"
"out vec4 vs_color; \n"
"void main(void) \n"
"{ \n"
" const vec4 vertices[] = vec4[](vec4( 0.25, -0.25, 0.5, 1.0), \n"
" vec4(-0.25, -0.25, 0.5, 1.0), \n"
" vec4( 0.25, 0.25, 0.5, 1.0)); \n"
" const vec4 colors[] = vec4[](vec4(1.0, 0.0, 0.0, 1.0), \n"
" vec4(0.0, 1.0, 0.0, 1.0), \n"
" vec4(0.0, 0.0, 1.0, 1.0)); \n"
" \n"
" gl_Position = vertices[gl_VertexID]; \n"
" vs_color = colors[gl_VertexID]; \n"
"} \n"
};
vs_source 안의
vs_color를 out으로 선언한후
static const char * fs_source[] =
{
"#version 420 core \n"
" \n"
"in vec4 vs_color; \n"
"out vec4 color; \n"
" \n"
"void main(void) \n"
"{ \n"
" color = vs_color; \n"
"} \n"
};
fs_source 안에서 vs_color를 in으로 받아서 color를 결정 한다.
