void Texture2D::present(Shader *shader) {
// One shared mesh for all texture presentation
static GLuint vao, vbo;
if (!glIsBuffer(vao)) {
GLfloat vertices[] = {
-1.0, -1.0, 0.0,
1.0, -1.0, 0.0,
-1.0, 1.0, 0.0,
1.0, 1.0, 0.0,
};
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, 48, vertices, GL_STATIC_DRAW);
GLint loc = shader->getAttribLocation("vPosition");
glEnableVertexAttribArray(loc);
glVertexAttribPointer(loc, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBlendFunc(GL_ONE, GL_ZERO);
glBindVertexArray(vao);
shader->use();
GLint texLoc = shader->getUniformLocation("texture0");
glUniform1i(texLoc, 0);
bindToUnit(GL_TEXTURE0);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
unbind();
}
void allocate(size_t new_width, size_t new_height)
{
width = new_width;
height = new_height;
size = height * width * bytes_per_pixel;
data = new unsigned char[size];
glGenTextures(1, &texture);
bindToUnit(GL_TEXTURE0);
glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_RECTANGLE, 0, FormatT::InternalFormat, width, height, 0, FormatT::Format, FormatT::Type, 0);
}
void Texture2D::present(Shader *shader) {
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBlendFunc(GL_ONE, GL_ZERO);
GLfloat vertices[] = {
-1.0, -1.0, 0.0,
1.0, -1.0, 0.0,
-1.0, 1.0, 0.0,
1.0, 1.0, 0.0,
};
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
shader->use();
bindToUnit(GL_TEXTURE0);
GLint loc = shader->getAttribLocation("vPosition");
glEnableVertexAttribArray(loc);
glVertexAttribPointer(loc, 3, GL_FLOAT, GL_FALSE, 0, vertices);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
unbind();
}
void upload()
{
bindToUnit(GL_TEXTURE0);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexSubImage2D(GL_TEXTURE_RECTANGLE, /*level*/0, /*xoffset*/0, /*yoffset*/0, width, height, FormatT::Format, FormatT::Type, data);
}
