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changing color triangle with vertex based color

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Nickiel12 2024-10-08 09:34:02 -07:00
parent 4f0ca1131f
commit c9d750f583
1 changed files with 137 additions and 60 deletions
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185
src/main.zig
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@ -2,36 +2,59 @@
//! you are building an executable. If you are making a library, the convention
//! is to delete this file and start with root.zig instead.
const std = @import("std");
const gl = @cImport ({
const gl = @cImport({
@cDefine("GLAD_GL_IMPLEMENTATION", "");
@cInclude("glad/glad.h");
@cInclude("GLFW/glfw3.h");
});
const vertexShaderSource: [*c]const u8 =
\\ #version 460 core
\\ layout (location = 0) in vec3 aPos;
\\ layout (location = 1) in vec3 aColor;
\\ out vec2 vertexColor;
\\
\\ void main() {
\\ gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
\\ vertexColor = vec2(aColor.x, aColor.y);
\\ }
;
;
const fragementShaderSource: [*c]const u8 =
\\ #version 330 core
\\ out vec4 FragColor;
\\
\\ uniform float zed_c;
\\ in vec2 vertexColor;
\\ void main() {
\\ FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
\\ FragColor = vec4(vertexColor.x, vertexColor.y, zed_c, 1.0f);
\\ }
;
;
const ShaderInitError = error {
const rectShaderSource: [*c]const u8 =
\\ #version 460 core
\\ layout (location = 0) in vec3 aPos;
\\ out vec2 vertexColor;
\\ void main() {
\\ gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
\\ vertexColor = vec2(aPos.x * 2.0f, aPos.y * 2.0f);
\\ }
;
const yellowShaderSource: [*c]const u8 =
\\ #version 460 core
\\ out vec4 FragColor;
\\ void main() {
\\ FragColor = vec4(0.8f, 0.8f, 0.1f, 1.0f);
\\ }
;
const ShaderInitError = error{
VertexCompilation,
FragementCompilation,
ShaderProgramLinking,
};
pub fn main() void {
// var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
@ -41,7 +64,7 @@ pub fn main() void {
const res: c_int = gl.glfwInit();
if (res != gl.GL_TRUE) {
std.debug.panic("Could not initialize glfw! Exit code: {d}", .{ res });
std.debug.panic("Could not initialize glfw! Exit code: {d}", .{res});
}
gl.glfwWindowHint(gl.GLFW_CONTEXT_VERSION_MAJOR, 4);
gl.glfwWindowHint(gl.GLFW_CONTEXT_VERSION_MINOR, 6);
@ -67,42 +90,39 @@ pub fn main() void {
// callback function returned?
_ = gl.glfwSetFramebufferSizeCallback(window, &framebuffer_resize_callback);
const vertexShader: c_uint = gl.glCreateShader(gl.GL_VERTEX_SHADER);
const fragShader: c_uint = gl.glCreateShader(gl.GL_FRAGMENT_SHADER);
const shaderProgram: c_uint = gl.glCreateProgram();
const orangeShaderProgram: c_uint = gl.glCreateProgram();
const yellowShaderProgram: c_uint = gl.glCreateProgram();
init_shader_program(&vertexShader, &fragShader, &shaderProgram) catch |e| switch (e) {
ShaderInitError.VertexCompilation => std.debug.panic("Could not compile vertex shader!\n", .{}),
ShaderInitError.FragementCompilation => std.debug.panic("Could not compile fragment shaders!\n", .{}),
ShaderInitError.ShaderProgramLinking => std.debug.panic("Could not link shader program!\n", .{}),
init_shader_program(&orangeShaderProgram, &yellowShaderProgram) catch |e| switch (e) {
ShaderInitError.VertexCompilation => std.debug.panic("Could not compile vertex shader!\n", .{}),
ShaderInitError.FragementCompilation => std.debug.panic("Could not compile fragment shaders!\n", .{}),
ShaderInitError.ShaderProgramLinking => std.debug.panic("Could not link shader program!\n", .{}),
};
var rect_vao: c_uint = undefined;
gl.glad_glGenVertexArrays.?(1, @ptrCast(&rect_vao));
gl.glad_glBindVertexArray.?(rect_vao);
const rect_verts: [4][3]f32 = .{ .{0.2, 0.2, 0.0}, .{0.8, 0.2, 0.0}, .{0.8, 0.4, 0.0}, .{0.2, 0.4, 0.0} };
const draw_indices: [2][3]c_uint = .{ .{0, 1, 3}, .{1, 2, 3} };
const rect_verts: [4][3]f32 = .{ .{ 0.2, 0.2, 0.0 }, .{ 0.8, 0.2, 0.0 }, .{ 0.8, 0.4, 0.0 }, .{ 0.2, 0.4, 0.0 } };
const draw_indices: [2][3]c_uint = .{ .{ 0, 1, 3 }, .{ 1, 2, 3 } };
var r_vert_buffer: c_uint = undefined;
gl.glad_glGenBuffers.?(1, &r_vert_buffer);
gl.glad_glBindBuffer.?(gl.GL_ARRAY_BUFFER, r_vert_buffer);
gl.glBufferData(gl.GL_ARRAY_BUFFER, 4 * 3 * @sizeOf(f32), @ptrCast(&rect_verts), gl.GL_STATIC_DRAW);
// VA-P needs to be defined on every vertex buffer so it knows how to read it
gl.glVertexAttribPointer(0, 3, gl.GL_FLOAT, gl.GL_FALSE, 3 * @sizeOf(f32), @ptrCast(&0));
// and then it needs to be enabled
gl.glEnableVertexAttribArray(0);
// gl.glad_glBindBuffer.?(0);
// but it doesn't need to be defined on the index buffer
var element_buffer: c_uint = undefined;
gl.glad_glGenBuffers.?(1, &element_buffer);
gl.glad_glBindBuffer.?(gl.GL_ELEMENT_ARRAY_BUFFER, element_buffer);
gl.glBufferData(gl.GL_ELEMENT_ARRAY_BUFFER, 2 * 3 * @sizeOf(c_uint), @ptrCast(&draw_indices), gl.GL_STATIC_DRAW);
// gl.glad_glBindBuffer.?(0);
gl.glEnableVertexAttribArray(0);
// ----- Simple Triangle ------
const verticies: [3][3]f32 = .{ .{-0.5, -0.5, 0.0}, .{0.5, -0.5, 0.0}, .{0.0, 0.5, 0.0} };
const verticies: [3][6]f32 = .{ .{ -0.5, -0.5, 0.0, 1.0, 0.2, 0.0 }, .{ 0.5, -0.5, 0.0, 0.2, 1.0, 0.0 }, .{ 0.0, 0.5, 0.0, 0.2, 0.2, 0.0 } };
// Vertex array object
var vao: c_uint = undefined;
gl.glad_glGenVertexArrays.?(1, @ptrCast(&vao));
@ -115,15 +135,21 @@ pub fn main() void {
// type of buffer, size of memory being inserted, the data to be loaded, how the GPU handles the memory
// STREAM - write once, used a few times, STATIC - set once, used many times, DYNAMIC - changed a lot
// used many times
gl.glBufferData(gl.GL_ARRAY_BUFFER, 4 * 3 * @sizeOf(f32), @ptrCast(&verticies), gl.GL_STATIC_DRAW);
gl.glBufferData(gl.GL_ARRAY_BUFFER, 3 * 6 * @sizeOf(f32), @ptrCast(&verticies), gl.GL_STATIC_DRAW);
// 0 for location=0 from shader
// 3 for number of attributes per stride,
// the type of data
// if we want it to be normalized
// offset of start of data
// The target virtual buffer object is defined by the current state from glVertexAttribPointer
gl.glVertexAttribPointer(0, 3, gl.GL_FLOAT, gl.GL_FALSE, 3 * @sizeOf(f32), @ptrCast(&0));
gl.glEnableVertexAttribArray(0);
gl.glVertexAttribPointer(0, 3, gl.GL_FLOAT, gl.GL_FALSE, 6 * @sizeOf(f32), @ptrCast(&0));
// location 1, offset of 3 f32s
gl.glEnableVertexAttribArray(1);
// gl.glVertexAttribPointer(1, 3, gl.GL_FLOAT, gl.GL_FALSE, 6 * @sizeOf(f32), @ptrCast(&(3 * @sizeOf(f32))));
const offset: [*c]c_uint = 3 * @sizeOf(f32);
gl.glVertexAttribPointer(1, 3, gl.GL_FLOAT, gl.GL_FALSE, 6 * @sizeOf(f32), @ptrCast(offset));
gl.glad_glBindVertexArray.?(0);
@ -135,33 +161,38 @@ pub fn main() void {
gl.glDisable(gl.GL_CULL_FACE);
while(gl.glfwWindowShouldClose(window) == 0)
{
var time: f64 = undefined;
var blue_val: f64 = undefined;
const color_loc: c_int = gl.glGetUniformLocation(orangeShaderProgram, "zed_c");
if (color_loc == -1) {
std.debug.panic("Could not get uniform location of zed_c!", .{});
}
while (gl.glfwWindowShouldClose(window) == 0) {
time = gl.glfwGetTime();
blue_val = (@sin(time) / 2.0) + 0.5;
gl.glfwPollEvents();
handle_input(window.?);
gl.glClearColor(0.2, 0.3, 0.4, 0.5); // state setting, follo wed by state using
gl.glClear(gl.GL_COLOR_BUFFER_BIT); // color buffer, depth buffer, and stencil buffer
gl.glUseProgram(shaderProgram);
// offset into vertexes, and count
gl.glUseProgram(orangeShaderProgram);
gl.glUniform1f(color_loc, @floatCast(blue_val));
gl.glad_glBindVertexArray.?(vao);
gl.glDrawArrays(gl.GL_TRIANGLES, 0, 3);
gl_err = gl.glGetError();
if (gl_err > 0) {
std.debug.print("There was an opengl error: {d}", .{gl_err});
gl_err = 0;
}
gl.glUseProgram(yellowShaderProgram);
gl.glad_glBindVertexArray.?(rect_vao);
gl.glDrawElements(gl.GL_TRIANGLES, 6, gl.GL_UNSIGNED_INT, null);
gl_err = gl.glGetError();
if (gl_err > 0) {
std.debug.print("There was an opengl error: {d}", .{gl_err});
std.debug.print("There was an opengl error: {d}\n", .{gl_err});
gl_err = 0;
}
@ -169,12 +200,17 @@ pub fn main() void {
gl.glfwSwapBuffers(window);
}
// These can't be defered. I think the program has to be
// deleted last
gl.glDeleteVertexArrays(1, &vao);
gl.glDeleteVertexArrays(1, &rect_vao);
gl.glDeleteBuffers(1, &vbo);
gl.glDeleteProgram(shaderProgram);
gl.glDeleteBuffers(1, &r_vert_buffer);
gl.glDeleteBuffers(1, &element_buffer);
gl.glDeleteProgram(orangeShaderProgram);
gl.glDeleteProgram(yellowShaderProgram);
gl.glfwTerminate();
}
export fn framebuffer_resize_callback(_: ?*gl.GLFWwindow, width: c_int, height: c_int) callconv(.C) void {
@ -187,46 +223,87 @@ fn handle_input(window: *gl.GLFWwindow) void {
}
}
fn init_shader_program(vertex_shader: *const c_uint, frag_shader: *const c_uint, program: *const c_uint) ShaderInitError!void {
fn init_shader_program(orange_program: *const c_uint, yellow_program: *const c_uint) ShaderInitError!void {
var success: c_int = undefined;
var infoLog: [512:0]u8 = undefined;
gl.glShaderSource(vertex_shader.*, 1, &vertexShaderSource, null);
gl.glCompileShader(vertex_shader.*);
gl.glGetShaderiv(vertex_shader.*, gl.GL_COMPILE_STATUS, &success);
const vertex_shader: c_uint = gl.glCreateShader(gl.GL_VERTEX_SHADER);
const rect_shader: c_uint = gl.glCreateShader(gl.GL_VERTEX_SHADER);
const orange_shader: c_uint = gl.glCreateShader(gl.GL_FRAGMENT_SHADER);
const yellow_shader: c_uint = gl.glCreateShader(gl.GL_FRAGMENT_SHADER);
gl.glShaderSource(vertex_shader, 1, &vertexShaderSource, null);
gl.glCompileShader(vertex_shader);
gl.glGetShaderiv(vertex_shader, gl.GL_COMPILE_STATUS, &success);
std.debug.print("Vertex Shader compiled\n", .{});
if (success == 0) {
std.debug.print("Shader compile failed!\n", .{});
gl.glGetShaderInfoLog(vertex_shader.*, 512, null, &infoLog);
gl.glGetShaderInfoLog(vertex_shader, 512, null, &infoLog);
std.debug.print("Error Log: {s}\n", .{infoLog});
return ShaderInitError.VertexCompilation;
}
gl.glShaderSource(frag_shader.*, 1, &fragementShaderSource, null);
gl.glCompileShader(frag_shader.*);
gl.glGetShaderiv(frag_shader.*, gl.GL_COMPILE_STATUS, &success);
gl.glShaderSource(orange_shader, 1, &fragementShaderSource, null);
gl.glCompileShader(orange_shader);
gl.glGetShaderiv(orange_shader, gl.GL_COMPILE_STATUS, &success);
std.debug.print("Fragment Shader compiled\n", .{});
if (success == 0) {
std.debug.print("Shader compile failed!\n", .{});
gl.glGetShaderInfoLog(frag_shader.*, 512, null, &infoLog);
gl.glGetShaderInfoLog(orange_shader, 512, null, &infoLog);
std.debug.print("Error Log: {s}\n", .{infoLog});
return ShaderInitError.FragementCompilation;
}
gl.glAttachShader(program.*, vertex_shader.*);
gl.glAttachShader(program.*, frag_shader.*);
gl.glLinkProgram(program.*);
gl.glAttachShader(orange_program.*, vertex_shader);
gl.glAttachShader(orange_program.*, orange_shader);
gl.glLinkProgram(orange_program.*);
std.debug.print("Shader Linking Complete\n", .{});
gl.glGetProgramiv(program.*, gl.GL_LINK_STATUS, &success);
gl.glGetProgramiv(orange_program.*, gl.GL_LINK_STATUS, &success);
if (success == 0) {
std.debug.print("Shader linking failed!\n", .{});
gl.glGetProgramInfoLog(program.*, 512, null, &infoLog);
gl.glGetProgramInfoLog(orange_program.*, 512, null, &infoLog);
std.debug.print("Error Log: {s}", .{infoLog});
return ShaderInitError.ShaderProgramLinking;
}
gl.glDeleteShader(vertex_shader.*);
gl.glDeleteShader(frag_shader.*);
gl.glShaderSource(rect_shader, 1, &rectShaderSource, null);
gl.glCompileShader(rect_shader);
gl.glGetShaderiv(rect_shader, gl.GL_COMPILE_STATUS, &success);
std.debug.print("Rectangle shader compiled!\n", .{});
if (success == 0) {
std.debug.print("Rectangle shader compile failed!\n", .{});
gl.glGetShaderInfoLog(rect_shader, 512, null, &infoLog);
std.debug.print("Error Log: {s}", .{infoLog});
return ShaderInitError.VertexCompilation;
}
gl.glShaderSource(yellow_shader, 1, &yellowShaderSource, null);
gl.glCompileShader(yellow_shader);
gl.glGetShaderiv(yellow_shader, gl.GL_COMPILE_STATUS, &success);
std.debug.print("Yellow Fragment shader compiled!\n", .{});
if (success == 0) {
std.debug.print("Yellow fragement shader compile failed!\n", .{});
gl.glGetShaderInfoLog(yellow_shader, 512, null, &infoLog);
std.debug.print("Error Log: {s}", .{infoLog});
return ShaderInitError.FragementCompilation;
}
gl.glAttachShader(yellow_program.*, rect_shader);
gl.glAttachShader(yellow_program.*, yellow_shader);
gl.glLinkProgram(yellow_program.*);
std.debug.print("Yellow Shader Linking Complete\n", .{});
gl.glGetProgramiv(orange_program.*, gl.GL_LINK_STATUS, &success);
if (success == 0) {
std.debug.print("Yellow Shader linking failed!\n", .{});
gl.glGetProgramInfoLog(orange_program.*, 512, null, &infoLog);
std.debug.print("Error Log: {s}", .{infoLog});
return ShaderInitError.ShaderProgramLinking;
}
gl.glDeleteShader(rect_shader);
gl.glDeleteShader(vertex_shader);
gl.glDeleteShader(orange_shader);
gl.glDeleteShader(yellow_shader);
std.debug.print("Shader program selected, cleaned up compiled shaders\n", .{});
}