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6. Coordinate Systems
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@brunodeangelis
brunodeangelis committed Dec 10, 2023
1 parent 610b206 commit 88809fa
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2 changes: 1 addition & 1 deletion constants.odin
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Expand Up @@ -6,7 +6,7 @@ GL_VERSION_MINOR :: 1
WINDOW_WIDTH :: 800
WINDOW_HEIGHT :: 600

SHADERS_EXTENSION :: ".glsl"
SHADERS_EXTENSION :: "glsl"
SHADERS_BASE_PATH :: "shaders"
SHADERS_VERTEX_SEPARATOR :: "#type vertex"
SHADERS_FRAGMENT_SEPARATOR :: "#type fragment"
134 changes: 91 additions & 43 deletions main.odin
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@@ -1,5 +1,5 @@
// 5. Transformations
// https://learnopengl.com/Getting-started/Transformations
// 6. Coordinate Systems
// https://learnopengl.com/Getting-started/Coordinate-Systems

package main

Expand All @@ -13,32 +13,76 @@ import "vendor:glfw"
import stbi "vendor:stb/image"

window: glfw.WindowHandle

rect_verts := [?]f32{
// xyz // texture coords
0.5, 0.5, 0.0, 2.0, 2.0, // TR
0.5, -0.5, 0.0, 2.0, 0.0, // BR
-0.5, -0.5, 0.0, 0.0, 0.0, // BL
-0.5, 0.5, 0.0, 0.0, 2.0, // TL
viewport: [4]i32

cube_verts := [?]f32 {
-0.5, -0.5, -0.5, 0.0, 0.0,
0.5, -0.5, -0.5, 1.0, 0.0,
0.5, 0.5, -0.5, 1.0, 1.0,
0.5, 0.5, -0.5, 1.0, 1.0,
-0.5, 0.5, -0.5, 0.0, 1.0,
-0.5, -0.5, -0.5, 0.0, 0.0,

-0.5, -0.5, 0.5, 0.0, 0.0,
0.5, -0.5, 0.5, 1.0, 0.0,
0.5, 0.5, 0.5, 1.0, 1.0,
0.5, 0.5, 0.5, 1.0, 1.0,
-0.5, 0.5, 0.5, 0.0, 1.0,
-0.5, -0.5, 0.5, 0.0, 0.0,

-0.5, 0.5, 0.5, 1.0, 0.0,
-0.5, 0.5, -0.5, 1.0, 1.0,
-0.5, -0.5, -0.5, 0.0, 1.0,
-0.5, -0.5, -0.5, 0.0, 1.0,
-0.5, -0.5, 0.5, 0.0, 0.0,
-0.5, 0.5, 0.5, 1.0, 0.0,

0.5, 0.5, 0.5, 1.0, 0.0,
0.5, 0.5, -0.5, 1.0, 1.0,
0.5, -0.5, -0.5, 0.0, 1.0,
0.5, -0.5, -0.5, 0.0, 1.0,
0.5, -0.5, 0.5, 0.0, 0.0,
0.5, 0.5, 0.5, 1.0, 0.0,

-0.5, -0.5, -0.5, 0.0, 1.0,
0.5, -0.5, -0.5, 1.0, 1.0,
0.5, -0.5, 0.5, 1.0, 0.0,
0.5, -0.5, 0.5, 1.0, 0.0,
-0.5, -0.5, 0.5, 0.0, 0.0,
-0.5, -0.5, -0.5, 0.0, 1.0,

-0.5, 0.5, -0.5, 0.0, 1.0,
0.5, 0.5, -0.5, 1.0, 1.0,
0.5, 0.5, 0.5, 1.0, 0.0,
0.5, 0.5, 0.5, 1.0, 0.0,
-0.5, 0.5, 0.5, 0.0, 0.0,
-0.5, 0.5, -0.5, 0.0, 1.0,
}
cube_positions := [?]v3{
{0, 0, 0},
{2, 5, -15},
{-1.5, -2.2, -2.5},
{-3.8, -2, -12.3},
{ 2.4, -0.4, -3.5},
{-1.7, 3, -7.5},
{1.3, -2, -2.5},
{1.5, 2, -2.5},
{1.5, 0.2, -1.5},
{-1.3, 1, -1.5},
}
rect_texture_coords := [?]f32{1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0}
grass_texture, face_texture: u32

indices := [?]u32{ // Zero-indexed
0, 1, 3, // First triangle
1, 2, 3 // Second triangle
}
tri_verts := [?]f32{
// xyz // rgb
0.5, 0.5, 0.0, 1.0, 0.0, 0.0,
0.75, -0.5, 0.0, 0.0, 1.0, 0.0,
0.25, -0.5, 0.0, 0.0, 0.0, 1.0
0.25, -0.5, 0.0, 0.0, 0.0, 1.0,
}

HOW_MANY :: 2
VAOs := make([]u32, HOW_MANY)
VBOs := make([]u32, HOW_MANY)
EBO, rect_shader, tri_shader: u32
cube_shader, tri_shader: u32

wireframe: bool

Expand All @@ -58,6 +102,8 @@ main :: proc() {
glfw.WindowHint(glfw.OPENGL_FORWARD_COMPAT, gl.TRUE)
}

viewport[2] = WINDOW_WIDTH
viewport[3] = WINDOW_HEIGHT
window = glfw.CreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "Hi mom!", nil, nil)
if window == nil {
fmt.print("Failed to create GLFW window\n")
Expand All @@ -73,15 +119,14 @@ main :: proc() {
gl.load_up_to(GL_VERSION_MAJOR, GL_VERSION_MINOR, glfw.gl_set_proc_address)
fmt.println(gl.GetString(gl.VERSION))

gl.Enable(gl.DEPTH_TEST)

gl.GenVertexArrays(HOW_MANY, raw_data(VAOs))
gl.GenBuffers(HOW_MANY, raw_data(VBOs))
gl.GenBuffers(1, &EBO)

gl.BindVertexArray(VAOs[0])
gl.BindBuffer(gl.ARRAY_BUFFER, VBOs[0])
gl.BufferData(gl.ARRAY_BUFFER, size_of(rect_verts), &rect_verts, gl.STATIC_DRAW)
gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, EBO)
gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, size_of(indices), &indices, gl.STATIC_DRAW)
gl.BufferData(gl.ARRAY_BUFFER, size_of(cube_verts), &cube_verts, gl.STATIC_DRAW)
gl.VertexAttribPointer(0, 3, gl.FLOAT, gl.FALSE, 5 * size_of(f32), 0)
gl.EnableVertexAttribArray(0)
gl.VertexAttribPointer(1, 2, gl.FLOAT, gl.FALSE, 5 * size_of(f32), 3 * size_of(f32))
Expand All @@ -95,7 +140,7 @@ main :: proc() {
gl.VertexAttribPointer(1, 3, gl.FLOAT, gl.FALSE, 6 * size_of(f32), 3 * size_of(f32))
gl.EnableVertexAttribArray(1)

rect_shader, _ = load_shader("rect")
cube_shader, _ = load_shader("cube")
tri_shader, _ = load_shader("triangle")

stbi.set_flip_vertically_on_load(1)
Expand Down Expand Up @@ -124,9 +169,9 @@ main :: proc() {
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, i32(image2_width), i32(image2_height), 0, gl.RGBA, gl.UNSIGNED_BYTE, image2_bytes)
gl.GenerateMipmap(gl.TEXTURE_2D)

use_shader(rect_shader)
set_uniform(rect_shader, "myTexture", 0)
set_uniform(rect_shader, "myTexture2", 1)
use_shader(cube_shader)
set_uniform(cube_shader, "myTexture", 0)
set_uniform(cube_shader, "myTexture2", 1)

for !glfw.WindowShouldClose(window) {
render()
Expand All @@ -135,42 +180,44 @@ main :: proc() {
}

render :: proc() {
using math
time := glfw.GetTime()

gl.ClearColor(0.2, 0.3, 0.3, 1.0)
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

if wireframe {
gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
} else {
gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
}

use_shader(rect_shader)
sin_time01 := sin(time) * 0.5 + 0.5
set_uniform(rect_shader, "myColor", v4{0.5, f32(sin_time01), 0.25, 1.0})
set_uniform(rect_shader, "alpha", texture_alpha)
transform := mat4(1)
transform *= lalg.matrix4_translate_f32({-0.5, 0, 0})
transform *= lalg.matrix4_rotate_f32(f32(time), {0, 0, 1})
transform *= lalg.matrix4_scale_f32(v3(1.5))
set_uniform(rect_shader, "transform", &transform)
use_shader(cube_shader)
view_mat := lalg.matrix4_translate_f32({0, 0, -5})
proj_mat := lalg.matrix4_perspective_f32(math.to_radians(f32(45)), f32(viewport[2]) / f32(viewport[3]), 0.01, 1000)
set_uniform(cube_shader, "view", &view_mat)
set_uniform(cube_shader, "projection", &proj_mat)
sin_time01 := math.sin(time) * 0.5 + 0.5
set_uniform(cube_shader, "myColor", v4{0.5, f32(sin_time01), 0.25, 1.0})
set_uniform(cube_shader, "alpha", texture_alpha)
gl.ActiveTexture(gl.TEXTURE0);
gl.BindTexture(gl.TEXTURE_2D, grass_texture)
gl.ActiveTexture(gl.TEXTURE1);
gl.BindTexture(gl.TEXTURE_2D, face_texture)
gl.BindVertexArray(VAOs[0])
gl.DrawElements(gl.TRIANGLES, len(indices), gl.UNSIGNED_INT, nil)
transform2 := mat4(1)
transform2 *= lalg.matrix4_translate_f32({0.5, 0, 0})
transform2 *= lalg.matrix4_rotate_f32(f32(-time), {0, 0, 1})
transform2 *= lalg.matrix4_scale_f32(v3(f32(sin_time01)))
set_uniform(rect_shader, "transform", &transform2)
gl.DrawElements(gl.TRIANGLES, len(indices), gl.UNSIGNED_INT, nil)
for pos, idx in cube_positions {
rotate_by := f32(20 * idx)
if idx % 3 == 0 {
rotate_by += f32(time * 2)
}
model_mat := lalg.matrix4_rotate_f32(rotate_by, {1, 0.3, 0.5})
model_mat = lalg.matrix4_translate_f32(pos) * model_mat
set_uniform(cube_shader, "model", &model_mat)

gl.DrawArrays(gl.TRIANGLES, 0, 36)
}

use_shader(tri_shader)
set_uniform(tri_shader, "yFactor", f32(sin(time) * 0.5))
set_uniform(tri_shader, "yFactor", f32(math.sin(time) * 0.5))
gl.BindVertexArray(VAOs[1])
gl.DrawArrays(gl.TRIANGLES, 0, 3)

Expand All @@ -183,6 +230,7 @@ fb_size_callback :: proc "c" (window: glfw.WindowHandle, width, height: i32) {
context = runtime.default_context()

gl.Viewport(0, 0, width, height)
gl.GetIntegerv(gl.VIEWPORT, &viewport[0]);
render() // Draw while resizing
}

Expand Down
2 changes: 1 addition & 1 deletion odinfmt.json
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@@ -1,6 +1,6 @@
{
"$schema": "https://raw.githubusercontent.com/DanielGavin/ols/master/misc/odinfmt.schema.json",
"character_width": 100,
"character_width": 120,
"tabs": true,
"tabs_width": 2
}
6 changes: 4 additions & 2 deletions shaders/rect.glsl → shaders/cube.glsl
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Expand Up @@ -3,13 +3,15 @@
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTextureCoord;

uniform mat4 transform;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;

out vec2 textureCoord;

void main()
{
gl_Position = transform * vec4(aPos, 1.0);
gl_Position = projection * view * model * vec4(aPos, 1.0);
textureCoord = aTextureCoord;
}

Expand Down
2 changes: 1 addition & 1 deletion utils.odin
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ import lalg "core:math/linalg"
import gl "vendor:OpenGL"

load_shader :: proc(name: string) -> (program: u32, success: bool) {
file_name, concat_err := strings.concatenate({name, SHADERS_EXTENSION})
file_name, concat_err := strings.concatenate({name, ".", SHADERS_EXTENSION})
if concat_err != nil {
return 0, false
}
Expand Down

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