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const std = @import("std");
const c_allocator = @import("std").heap.c_allocator;
const panic = @import("std").debug.panic;
const c = @import("c.zig");
pub const ShaderProgram = struct {
program_id: c.GLuint,
vert_id: c.GLuint,
frag_id: c.GLuint,
pub fn bind(self: ShaderProgram) void {
c.glUseProgram(self.program_id);
}
pub fn attribLocation(self: ShaderProgram, name: [*]const u8) c.GLint {
const id = c.glGetAttribLocation(self.program_id, name);
if (id == -1) {
panic("invalid attrib: {}\n", .{name});
}
return id;
}
pub fn uniformLocation(self: ShaderProgram, name: [*]const u8) c.GLint {
const id = c.glGetUniformLocation(self.program_id, name);
if (id == -1) {
panic("invalid uniform: {}\n", .{name});
}
return id;
}
pub fn setUniformInt(self: ShaderProgram, uniform_id: c.GLint, value: c_int) void {
c.glUniform1i(uniform_id, value);
}
pub fn setUniformFloat(self: ShaderProgram, uniform_id: c.GLint, value: f32) void {
c.glUniform1f(uniform_id, value);
}
pub fn setUniformVec2(self: ShaderProgram, uniform_id: c.GLint, value: [2]f32) void {
c.glUniform3fv(uniform_id, 1, value.ptr);
}
pub fn setUniformVec3(self: ShaderProgram, uniform_id: c.GLint, value: [3]f32) void {
c.glUniform3fv(uniform_id, 1, value.ptr);
}
pub fn setUniformVec4(self: ShaderProgram, uniform_id: c.GLint, value: [4]f32) void {
c.glUniform4fv(uniform_id, 1, value.ptr);
}
pub fn setUniformMat4x4(self: ShaderProgram, uniform_id: c.GLint, value: [4][4]f32) void {
c.glUniformMatrix4fv(uniform_id, 1, c.GL_FALSE, &value[0][0]);
}
pub fn create(vert_source: []const u8, frag_source: []const u8) !ShaderProgram {
var self: ShaderProgram = undefined;
self.vert_id = try initGlShader(vert_source, "vertex", c.GL_VERTEX_SHADER);
errdefer c.glDeleteShader(self.vert_id);
self.frag_id = try initGlShader(frag_source, "fragment", c.GL_FRAGMENT_SHADER);
errdefer c.glDeleteShader(self.frag_id);
self.program_id = c.glCreateProgram();
c.glAttachShader(self.program_id, self.vert_id);
c.glAttachShader(self.program_id, self.frag_id);
c.glLinkProgram(self.program_id);
errdefer c.glDeleteProgram(self.program_id);
errdefer c.glDetachShader(self.program_id, self.frag_id);
errdefer c.glDetachShader(self.program_id, self.vert_id);
var ok: c.GLint = undefined;
c.glGetProgramiv(self.program_id, c.GL_LINK_STATUS, &ok);
if (ok != 0) return self;
var error_size: c.GLint = undefined;
c.glGetProgramiv(self.program_id, c.GL_INFO_LOG_LENGTH, &error_size);
const message = try c_allocator.alloc(u8, @intCast(usize, error_size));
c.glGetProgramInfoLog(self.program_id, error_size, &error_size, message.ptr);
std.debug.warn("Error linking shader program: {s}\n", .{ @ptrCast([*:0]const u8, message.ptr) });
return error.LinkError;
}
pub fn destroy(self: *ShaderProgram) void {
c.glDetachShader(self.program_id, self.frag_id);
c.glDetachShader(self.program_id, self.vert_id);
c.glDeleteShader(self.frag_id);
c.glDeleteShader(self.vert_id);
c.glDeleteProgram(self.program_id);
}
};
fn initGlShader(source: []const u8, name: []const u8, kind: c.GLenum) !c.GLuint {
const shader_id = c.glCreateShader(kind);
errdefer c.glDeleteShader(shader_id);
const source_ptr: ?[*]const u8 = source.ptr;
const source_len = @intCast(c.GLint, source.len);
c.glShaderSource(shader_id, 1, &source_ptr, &source_len);
c.glCompileShader(shader_id);
var ok: c.GLint = undefined;
c.glGetShaderiv(shader_id, c.GL_COMPILE_STATUS, &ok);
if (ok != 0) return shader_id;
var error_size: c.GLint = undefined;
c.glGetShaderiv(shader_id, c.GL_INFO_LOG_LENGTH, &error_size);
const message = try c_allocator.alloc(u8, @intCast(usize, error_size));
c.glGetShaderInfoLog(shader_id, error_size, &error_size, message.ptr);
std.debug.warn("Error compiling {s} shader:\n{s}\n", .{ name, @ptrCast([*:0]const u8, message.ptr) });
return error.CompileError;
}
pub const FramebufferObject = struct {
buffer_id: c.GLuint,
texture_id: c.GLuint,
pub fn bind(self: FramebufferObject) void {
c.glBindFramebuffer(c.GL_FRAMEBUFFER, self.buffer_id);
}
pub fn unbind(self: FramebufferObject) void {
c.glBindFramebuffer(c.GL_FRAMEBUFFER, 0);
}
pub fn create(width: i32, height: i32) !FramebufferObject {
var self: FramebufferObject = undefined;
c.glGenFramebuffers(1, &self.buffer_id);
c.glBindFramebuffer(c.GL_FRAMEBUFFER, self.buffer_id);
c.glGenTextures(1, &self.texture_id);
c.glBindTexture(c.GL_TEXTURE_2D, self.texture_id);
c.glTexImage2D(c.GL_TEXTURE_2D, 0, c.GL_RGBA, width, height, 0, c.GL_RGBA, c.GL_UNSIGNED_BYTE, null);
c.glTexParameteri(c.GL_TEXTURE_2D, c.GL_TEXTURE_MIN_FILTER, c.GL_LINEAR);
c.glTexParameteri(c.GL_TEXTURE_2D, c.GL_TEXTURE_MAG_FILTER, c.GL_LINEAR);
c.glBindTexture(c.GL_TEXTURE_2D, 0);
c.glFramebufferTexture2D(c.GL_FRAMEBUFFER, c.GL_COLOR_ATTACHMENT0, c.GL_TEXTURE_2D, self.texture_id, 0);
if (c.glCheckFramebufferStatus(c.GL_FRAMEBUFFER) != c.GL_FRAMEBUFFER_COMPLETE)
return error.FBONotComplete;
c.glBindFramebuffer(c.GL_FRAMEBUFFER, 0);
return self;
}
pub fn destroy(self: *FramebufferObject) void {
c.glDeleteFramebuffers(1, &self.*.buffer_id);
c.glDeleteTextures(1, &self.*.texture_id);
}
};
pub const VertexObject = struct {
array_id: c.GLuint,
buffer_id: c.GLuint,
vertex_size: i32,
vertex_count: i32,
pub fn bind(self: VertexObject, attrib: u32) void {
c.glBindBuffer(c.GL_ARRAY_BUFFER, self.buffer_id);
c.glEnableVertexAttribArray(attrib);
c.glVertexAttribPointer(attrib, self.vertex_size, c.GL_FLOAT, c.GL_FALSE, 0, null);
}
pub fn draw(self: VertexObject) void {
c.glDrawArrays(c.GL_TRIANGLE_STRIP, 0, self.vertex_count);
}
pub fn create(comptime T: type, vertices: []const T, vertex_size: i32) VertexObject {
var self: VertexObject = undefined;
self.vertex_size = vertex_size;
self.vertex_count = @intCast(i32, vertices.len);
c.glGenVertexArrays(1, &self.array_id);
c.glBindVertexArray(self.array_id);
c.glGenBuffers(1, &self.buffer_id);
c.glBindBuffer(c.GL_ARRAY_BUFFER, self.buffer_id);
c.glBufferData(c.GL_ARRAY_BUFFER,
@intCast(c_long, @sizeOf(T) * vertices.len),
@ptrCast(*const c_void, &vertices[0]),
c.GL_STATIC_DRAW);
return self;
}
pub fn destroy(self: *VertexObject) void {
defer c.glDeleteBuffers(1, &self.*.buffer_id);
defer c.glDeleteVertexArrays(1, &self.*.array_id);
}
};
pub const Constants = struct {
textureShader: ShaderProgram,
normalizedQuad: VertexObject,
main_window: *c.GLFWwindow,
pub fn create(main_window: *c.GLFWwindow) !Constants {
var self: Constants = undefined;
c.glfwMakeContextCurrent(main_window);
self.main_window = main_window;
self.textureShader = try ShaderProgram.create(
\\#version 330 core
\\
\\layout(location = 0) in vec2 position;
\\out vec2 uv;
\\
\\void main() {
\\ uv = position / 2.0 + 0.5;
\\ gl_Position = vec4(position, 0, 1);
\\}
,
\\#version 330 core
\\
\\in vec2 uv;
\\out vec4 color;
\\
\\uniform sampler2D colorTexture;
\\
\\void main(){
\\ color = texture(colorTexture, uv);
\\}
);
const vertices = [_]c.GLfloat{
-1.0, -1.0,
-1.0, 1.0,
1.0, -1.0,
1.0, 1.0,
};
self.normalizedQuad = VertexObject.create(f32, vertices[0..], 2);
return self;
}
pub fn destroy(self: *Constants) void {
self.normalizedQuad.destroy();
self.textureShader.destroy();
}
};
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