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TextRenderProgram.cpp
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TextRenderProgram.cpp
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#include "TextRenderProgram.hpp"
#include "gl_compile_program.hpp"
#include "gl_errors.hpp"
Load< TextRenderProgram > text_render_program(LoadTagEarly);
TextRenderProgram::TextRenderProgram() {
//Compile vertex and fragment shaders using the convenient 'gl_compile_program' helper function:
program = gl_compile_program(
//vertex shader:
"#version 330\n"
"uniform mat4 OBJECT_TO_CLIP;\n"
"uniform vec2 OFFSET;\n"
"in vec4 Position;\n"
"in vec2 TexCoord;\n"
"out vec2 texCoord;\n"
"void main() {\n"
" gl_Position = OBJECT_TO_CLIP * (vec4(OFFSET, 0.0, 0.0) + Position);\n"
" texCoord = TexCoord;\n"
"}\n"
,
//fragment shader:
"#version 330\n"
"uniform sampler2D TEX;\n"
"uniform vec4 COLOR;\n"
"in vec2 texCoord;\n"
"out vec4 fragColor;\n"
"void main() {\n"
" fragColor = COLOR.rgba * vec4(1.0, 1.0, 1.0, texelFetch(TEX, ivec2(texCoord.xy), 0).r);\n"
"}\n"
);
//look up the locations of vertex attributes:
Position_vec2 = glGetAttribLocation(program, "Position");
TexCoord_vec2 = glGetAttribLocation(program, "TexCoord");
//look up the locations of uniforms:
OBJECT_TO_CLIP_mat4 = glGetUniformLocation(program, "OBJECT_TO_CLIP");
COLOR_vec4 = glGetUniformLocation(program, "COLOR");
OFFSET_vec2 = glGetUniformLocation(program, "OFFSET");
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
}
TextRenderProgram::~TextRenderProgram() {
glDeleteProgram(program);
program = 0;
}