Texture2DProgram.cpp

#include "Texture2DProgram.hpp"

#include "gl_compile_program.hpp"
#include "gl_errors.hpp"

Load<Texture2DProgram> texture2d_program(LoadTagEarly);

Texture2DProgram::Texture2DProgram() {
	//Compile vertex and fragment shaders using the convenient 'gl_compile_program' helper function:
	program = gl_compile_program(
		//vertex shader:
		"#version 330\n"
		"in vec4 Position;\n"
		"in vec4 Color;\n"
		"in vec2 TexCoord;\n"
		"out vec2 texCoord;\n"
		"out vec4 color;\n"
		"void main() {\n"
		"	gl_Position = Position;\n"
		"	texCoord = TexCoord;\n"
		"	color = Color;\n"
		"}\n"
	,
		//fragment shader:
		"#version 330\n"
		"uniform sampler2D TEX;\n"
		"in vec4 color;\n"
		"in vec2 texCoord;\n"
		"out vec4 fragColor;\n"
		"void main() {\n"
		"	fragColor = texture(TEX, texCoord) * color;\n"
		"}\n"
	);
	//As you can see above, adjacent strings in C/C++ are concatenated.
	// this is very useful for writing long shader programs inline.

	//look up the locations of vertex attributes:
	Position_vec4 = glGetAttribLocation(program, "Position");
	Color_vec4 = glGetAttribLocation(program, "Color");
	TexCoord_vec2 = glGetAttribLocation(program, "TexCoord");

	//look up the locations of uniforms:
	GLuint TEX_sampler2D = glGetUniformLocation(program, "TEX");

	//set TEX to always refer to texture binding zero:
	glUseProgram(program); //bind program -- glUniform* calls refer to this program now

	glUniform1i(TEX_sampler2D, 0); //set TEX to sample from GL_TEXTURE0

	glUseProgram(0); //unbind program -- glUniform* calls refer to ??? now
}

Texture2DProgram::~Texture2DProgram() {
	glDeleteProgram(program);
	program = 0;
}
// source: https://github.com/GenBrg/MarryPrincess/blob/master/Texture2DProgram.cpp#L81
GLuint Texture2DProgram::GetVao(GLuint vertex_buffer) const
{
    GLuint vao;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);
    glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);

    glEnableVertexAttribArray(Position_vec4);
    glVertexAttribPointer(Position_vec4, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const void*)offsetof(Vertex, Position));

	glEnableVertexAttribArray(Color_vec4);
    glVertexAttribPointer(Color_vec4, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(Vertex), (const void*)offsetof(Vertex, Color));

    glEnableVertexAttribArray(TexCoord_vec2);
    glVertexAttribPointer(TexCoord_vec2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const void*)offsetof(Vertex, TexCoord));

    return vao;
}