345 lines
7.8 KiB
D
345 lines
7.8 KiB
D
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module gl;
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import glad.gl.all;
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import core.stdc.stdio;
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bool checkShaderError(GLuint shader, GLuint flag, bool is_program, in char[] shader_path) nothrow {
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GLint result;
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(is_program) ? glGetProgramiv(shader, flag, &result)
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: glGetShaderiv(shader, flag, &result);
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if (result == GL_FALSE) {
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GLchar[256] log; //FIXME this is potentially fatal
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(is_program) ? glGetProgramInfoLog(shader, log.sizeof, null, log.ptr)
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: glGetShaderInfoLog(shader, log.sizeof, null, log.ptr);
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printf("[OpenGL] Error in %s: %s\n", shader_path.ptr, log.ptr);
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return false;
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}
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return true;
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} // checkShaderError
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struct PixelBuffer {
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struct Shader {
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private {
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GLuint shader_prog;
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}
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@disable this(this);
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void compile(const (GLchar*)* vs_source, const (GLchar*)* fs_source) {
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import core.stdc.stdlib : exit;
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GLuint new_vs_shader = glCreateShader(GL_VERTEX_SHADER);
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glShaderSource(new_vs_shader, 1, vs_source, null);
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glCompileShader(new_vs_shader);
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if (!checkShaderError(new_vs_shader, GL_COMPILE_STATUS, false, "vertex_shader")) {
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exit(-1);
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}
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GLuint new_fs_shader = glCreateShader(GL_FRAGMENT_SHADER);
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glShaderSource(new_fs_shader, 1, fs_source, null);
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glCompileShader(new_fs_shader);
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if (!checkShaderError(new_fs_shader, GL_COMPILE_STATUS, false, "fragment_shader")) {
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exit(-1);
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}
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GLuint new_shader = glCreateProgram();
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glAttachShader(new_shader, new_vs_shader);
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glAttachShader(new_shader, new_fs_shader);
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// glBindAttribLocation(new_shader, 0, "screen_size");
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glLinkProgram(new_shader);
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if (!checkShaderError(new_shader, GL_LINK_STATUS, true, "shader_program")) {
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exit(-1);
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}
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glValidateProgram(new_shader);
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if (!checkShaderError(new_shader, GL_VALIDATE_STATUS, true, "shader_program")) {
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exit(-1);
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}
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shader_prog = new_shader;
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} // compile
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void setUniforms(int w, int h) {
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auto attr_loc = glGetUniformLocation(shader_prog, "screen_size");
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glUniform2f(attr_loc, cast(float)w, cast(float)h);
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} // setUniforms
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void bind() {
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glUseProgram(shader_prog);
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} // bind
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void unbind() {
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glUseProgram(0);
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} // unbind
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} // Shader
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struct Texture {
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import derelict.sdl2.sdl;
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import derelict.sdl2.image;
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private {
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GLuint texture_; //OpenGL handle for texture
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GLenum input_format_, output_format_, data_type_;
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int width_, height_;
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}
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@property @nogc nothrow {
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int width() const { return width_; }
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int height() const { return height_; }
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GLuint handle() { return texture_; }
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}
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@disable this(this);
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nothrow @nogc
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this(int width, int height, GLenum input_format, GLenum output_format, GLenum unpack_alignment) {
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width_ = width;
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height_ = height;
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input_format_ = input_format;
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output_format_ = output_format;
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data_type_ = GL_UNSIGNED_BYTE;
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glGenTextures(1, &texture_);
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glBindTexture(GL_TEXTURE_2D, texture_);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glPixelStorei(GL_UNPACK_ALIGNMENT, unpack_alignment);
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glTexImage2D(GL_TEXTURE_2D, 0, input_format_, width_, height_, 0, output_format_, GL_UNSIGNED_BYTE, cast(void*)0);
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glBindTexture(GL_TEXTURE_2D, 0);
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} //this
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nothrow @nogc
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void create(void* pixels, int width, int height, GLenum input_format = GL_RGB, GLenum output_format = GL_RGB, GLenum data_type = GL_UNSIGNED_BYTE) {
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width_ = width;
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height_ = height;
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input_format_ = input_format;
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output_format_ = output_format;
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data_type_ = data_type;
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//generate single texture, put handle in texture
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glGenTextures(1, &texture_);
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//normal 2d texture, bind to our texture handle
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glBindTexture(GL_TEXTURE_2D, texture_);
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//set texture parameters in currently bound texture, controls texture wrapping (or GL_CLAMP?)
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
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//linearly interpolate between pixels, MIN if texture is too small for drawing area, MAG if drawing area is smaller than texture
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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//texture type, level, format to store as, width, height, border, format loaded in
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glTexImage2D(GL_TEXTURE_2D, 0, input_format_, width_, height_, 0, output_format_, data_type_, pixels);
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//UNBIND
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glBindTexture(GL_TEXTURE_2D, 0);
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} // this
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~this() nothrow @nogc {
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if (texture_ != 0) {
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glDeleteTextures(1, &texture_);
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}
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} // ~this
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/**
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* Binds the texture handle, takes an argument for which texture unit to use.
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*/
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nothrow @nogc
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void bind(int unit) {
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assert(unit >= 0 && unit <= 31);
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glActiveTexture(GL_TEXTURE0 + unit); //since this is sequential, this works
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glBindTexture(GL_TEXTURE_2D, texture_);
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} // bind
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nothrow @nogc
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void unbind() {
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glBindTexture(GL_TEXTURE_2D, 0);
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} // unbind
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/**
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* Updates the texture in place given the new texture buffer.
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* Takes an optional offset to update only a part of the texture.
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**/
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nothrow @nogc
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void update(void[] pixels, size_t offset = 0) {
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bind(0);
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glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width_, height_, input_format_, data_type_, pixels.ptr);
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unbind();
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} // update
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} // Texture
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/**
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* Generic VertexArray structure, used to upload data of any given vertex type to the GPU.
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*/
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struct VertexArray {
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private {
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GLuint vao_;
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GLuint vbo_;
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GLenum type_; // type of vertex data, GL_TRIANGLES etc
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uint num_vertices_;
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}
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@disable this(this);
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nothrow @nogc
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void create(in float[2][] vertices, GLenum draw_type = GL_STATIC_DRAW, GLenum primitive = GL_TRIANGLES) {
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this.num_vertices_ = cast(uint)vertices.length;
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this.type_ = primitive;
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glGenVertexArrays(1, &vao_);
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glBindVertexArray(vao_);
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glGenBuffers(1, &vbo_);
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glBindBuffer(GL_ARRAY_BUFFER, vbo_);
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glBufferData(GL_ARRAY_BUFFER, vertices.length * vertices[0].sizeof, vertices.ptr, draw_type);
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// pos
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(0,
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2,
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GL_FLOAT,
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GL_FALSE,
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float.sizeof * 2,
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null
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);
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glBindVertexArray(0);
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} // this
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~this() nothrow @nogc {
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if (vao_ != 0) {
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glDeleteVertexArrays(1, &vao_);
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}
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} // ~this
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void bind() nothrow @nogc {
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glBindVertexArray(vao_);
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} // bind
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void draw() nothrow @nogc {
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glDrawArrays(type_, 0, num_vertices_);
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} // draw
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void unbind() nothrow @nogc {
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glBindVertexArray(0);
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} // unbind
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} // VertexArray
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const char* vs_shader = q{
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#version 330 core
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uniform vec2 screen_size;
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layout(location = 0) in vec2 pos;
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out vec2 frag_uv;
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void main() {
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gl_Position = vec4(pos, 0.0, 1.0);
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frag_uv = clamp(pos, vec2(0.0, 0.0), vec2(1.0, 1.0));
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}
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};
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const char* fs_shader = q{
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#version 330 core
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uniform sampler2D tex;
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in vec2 frag_uv;
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out vec4 out_col;
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void main() {
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float v = texture(tex, frag_uv.st).r * 255;
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out_col = vec4(v, v, v, 1.0);
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}
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};
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Shader shader;
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VertexArray vao;
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Texture tex;
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void create(void* pixels, int w, int h) {
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float[2][6] rect = [
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[-1.0f, -1.0f], // top left
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[1.0f, -1.0f], // top right
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[1.0f, 1.0f], // bottom right
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[-1.0f, -1.0f], // top left
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[-1.0f, 1.0f], // bottom left
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[1.0f, 1.0f], // bottom right
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];
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vao.create(rect[]);
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tex.create(pixels, w, h, GL_RED, GL_RED);
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shader.compile(&vs_shader, &fs_shader);
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} // create
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void draw(int screen_w, int screen_h) {
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vao.bind();
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shader.bind();
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shader.setUniforms(screen_w, screen_h);
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tex.bind(0);
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vao.draw();
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} // draw
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nothrow @nogc
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void update(void[] pixels, size_t offset = 0) {
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tex.update(pixels, offset);
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} // update
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} // PixelBuffer
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