require 'honey.std'


local glfw = honey.glfw
local gl = honey.gl
local Vec3 = honey.Vec3
local Mat4 = honey.Mat4


local window = honey.init()
gl.Enable(gl.DEPTH_TEST)


local model = Mat4()
model:identity()

local view = Mat4()
view:identity()
view:translate(Vec3{0, 0, -3})

local projection = Mat4()
projection:perspective(math.rad(45), 640/480, 0.1, 100)


local vertexShaderSource = [[
#version 410 core
layout (location = 0) in vec3 in_position;
layout (location = 1) in vec3 in_normal;
layout (location = 2) in vec2 in_tex;

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

out vec3 position;
out vec3 normal;
out vec2 tex;

void main()
{
    gl_Position = projection * view * model * vec4(in_position, 1.0);
    position = in_position;
    //normal = vec3(model * vec4(in_normal, 1.0f));
    normal = in_normal;
    tex = in_tex;
}
]]

local fragmentShaderSource = [[
#version 410 core
out vec4 FragColor;

in vec3 position;
in vec3 normal;
in vec2 tex;

uniform sampler2D ourTexture;

void main()
{
    FragColor = vec4(normal, 1.0f);
    //FragColor = vec4(tex, 1.0f, 1.0f);
    //FragColor = texture(ourTexture, TexCoord);
}
]]

-- vertex shader
local vertexShader = gl.CreateShader(gl.VERTEX_SHADER)
gl.ShaderSource(vertexShader, vertexShaderSource)
gl.CompileShader(vertexShader)

-- fragment shader
local fragmentShader = gl.CreateShader(gl.FRAGMENT_SHADER)
gl.ShaderSource(fragmentShader, fragmentShaderSource)
gl.CompileShader(fragmentShader)

-- link
local shader = gl.CreateProgram()
gl.AttachShader(shader, vertexShader)
gl.AttachShader(shader, fragmentShader)
gl.LinkProgram(shader)
-- clean up
gl.DeleteShader(vertexShader)
gl.DeleteShader(fragmentShader)


local mesh = honey.mesh.loadFile("assets/tetrahedron.obj")[1]
--local mesh = honey.mesh.Mesh(
--	{
--		0, 0, 0,    0, 0, 1,   0, 0,
--		1, 0, 0,    0, 0, 1,   1, 0,
--		0, 1, 0,    0, 0, 1,   0, 1,
--	},
--	{ 0, 2, 1 }
--)



while not window:shouldClose() do
	local time = glfw.GetTime()
	model:identity()
	model:rotateY(0.5 * math.pi * time)
	model:rotateX(0.05 * math.pi * time)
	--model:scale(0.2 * Vec3{1, 1, 1})

	gl.ClearColor(0.2, 0.4, 1.0, 1.0)
	gl.Clear(gl.COLOR_BUFFER_BIT + gl.DEPTH_BUFFER_BIT)

	gl.UseProgram(shader)

	local modelLocation = gl.GetUniformLocation(shader, "model")
	local viewLocation = gl.GetUniformLocation(shader, "view")
	local projectionLocation = gl.GetUniformLocation(shader, "projection")

	gl.UniformMatrix4fv(modelLocation, false, model.data)
	gl.UniformMatrix4fv(viewLocation, false, view.data)
	gl.UniformMatrix4fv(projectionLocation, false, projection.data)

	mesh:drawElements()


	window:swapBuffers()
	glfw.PollEvents()
end

honey.terminate()