bradgrantham-apple2e/gl_utility.h
2018-10-15 21:11:17 -07:00

108 lines
2.5 KiB
C++

#if !defined(__GLWIDGET_H__)
#define __GLWIDGET_H__
#if defined(__linux__)
#include <GL/glew.h>
#endif // defined(__linux__)
#define GLFW_INCLUDE_GLCOREARB
#include <GLFW/glfw3.h>
#include <vector>
#include <string>
void CheckOpenGL(const char *filename, int line);
bool CheckShaderCompile(GLuint shader, const std::string& shader_name);
bool CheckProgramLink(GLuint program);
struct vertex_attribute_buffer
{
GLuint buffer;
GLuint which;
GLuint count;
GLenum type;
GLboolean normalized;
GLsizei stride;
void bind() const
{
glBindBuffer(GL_ARRAY_BUFFER, buffer);
CheckOpenGL(__FILE__, __LINE__);
glVertexAttribPointer(which, count, type, normalized, stride, 0);
CheckOpenGL(__FILE__, __LINE__);
glEnableVertexAttribArray(which);
CheckOpenGL(__FILE__, __LINE__);
}
};
struct vertex_array : public std::vector<vertex_attribute_buffer>
{
void bind()
{
for(auto attr : *this) {
attr.bind();
}
}
};
/*
* OpenGL Render Target ; creates a framebuffer that can be used as a
* rendering target and as a texture color source.
*/
struct render_target
{
GLuint framebuffer;
GLuint color;
GLuint depth;
render_target(int w, int h);
~render_target();
// Start rendering; Draw()s will draw to this framebuffer
void start_rendering()
{
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, framebuffer);
}
// Stop rendering; Draw()s will draw to the back buffer
void stop_rendering()
{
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
}
// Start reading; Read()s will read from this framebuffer
void start_reading()
{
glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
glReadBuffer(GL_COLOR_ATTACHMENT0);
}
// Stop reading; Read()s will read from the back buffer
void stop_reading()
{
glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
glReadBuffer(GL_BACK);
}
// Use this color as the currently bound texture source
void use_color()
{
glBindTexture(GL_TEXTURE_2D, color);
}
};
struct opengl_texture
{
int w;
int h;
GLuint t;
operator GLuint() const { return t; }
};
opengl_texture initialize_texture(int w, int h, unsigned char *pixels = NULL);
GLuint GenerateProgram(const std::string& shader_name, const std::string& vertex_shader_text, const std::string& fragment_shader_text);
GLuint make_rectangle_array_buffer(float x, float y, float w, float h);
#endif /* __GLWIDGET_H__ */