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local gl = honey.gl
local window = honey.window
--====== initialize opengl ======--
gl.Init()
window.setHint(window.hintType.contextVersionMajor, 3)
window.setHint(window.hintType.contextVersionMinor, 3)
window.setHint(window.hintType.openGlProfile, window.profileType.openGlCoreProfile)
--====== create window ======--
local w = window.create(640, 480, 'hello, world!')
window.makeContextCurrent(w)
gl.InitGlad()
window.setFramebufferSizeCallback(w, function(_, width, height)
print(string.format("resize: (%d, %d)", width, height))
gl.setViewport(0, 0, width, height)
end)
--====== compile shaders ======--
local vertexShaderSource = [[
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;
uniform mat4 transform;
out vec3 ourColor;
out vec2 TexCoord;
void main()
{
gl_Position = transform * vec4(aPos, 1.0);
ourColor = aColor;
TexCoord = aTexCoord;
}
]]
local fragmentShaderSource = [[
#version 330 core
out vec4 FragColor;
in vec3 ourColor;
in vec2 TexCoord;
uniform sampler2D ourTexture;
void main()
{
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)
--====== set up vertex data ======--
local vertices = {
-- positions colors uvs
0.5, 0.5, 0.0, 1.0, 0.0, 0.0, 1.0, 1.0, -- top right
0.5, -0.5, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, -- bottom right
-0.5, -0.5, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, -- bottom let
-0.5, 0.5, 0.0, 1.0, 1.0, 0.0, 0.0, 1.0 -- top let
}
local indices = {
0, 1, 3, -- first triangle
1, 2, 3 -- second triangle
}
-- buffers
local vertexArray = gl.GenVertexArrays()
local vertexBuffer = gl.GenBuffers()
local elementBuffer = gl.GenBuffers()
gl.BindVertexArray(vertexArray)
gl.BindBuffer(gl.ARRAY_BUFFER, vertexBuffer)
gl.BufferData(gl.ARRAY_BUFFER, gl.FLOAT, vertices, gl.STATIC_DRAW)
gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, elementBuffer)
gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, gl.UNSIGNED_INT, indices, gl.STATIC_DRAW)
-- position
gl.VertexAttribPointer(0, 3, false, 8, 0)
gl.EnableVertexAttribArray(0)
-- color
gl.VertexAttribPointer(1, 3, false, 8, 3)
gl.EnableVertexAttribArray(1)
-- uv
gl.VertexAttribPointer(2, 2, false, 8, 6)
gl.EnableVertexAttribArray(2)
--====== load texture ======--
local texture = gl.GenTextures()
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
local image, width, height = honey.image.load('container.jpg', 3)
gl.TexImage2D(
gl.TEXTURE_2D, 0,
gl.RGB, width, height,
gl.RGB, gl.UNSIGNED_BYTE,
image
)
gl.GenerateMipmap(gl.TEXTURE_2D)
honey.image.destroy(image)
-- connect shader samplers to texture units
gl.UseProgram(shader)
gl.Uniform1i(gl.GetUniformLocation(shader, 'ourTexture'), 0)
--====== main loop ======--
local transform = honey.glm.mat4()
while not window.shouldClose(w) do
gl.ClearColor(0.2, 0.3, 0.3, 1.0)
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.ActiveTexture(0)
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.UseProgram(shader)
honey.glm.mat4_identity(transform)
local time = window.getTime()
honey.glm.rotate_z(transform, time, transform)
local transformLocation = gl.GetUniformLocation(shader, 'transform')
gl.UniformMatrix4fv(transformLocation, false, transform)
gl.BindVertexArray(vertexArray)
gl.DrawElements(gl.TRIANGLES, 6, gl.UNSIGNED_INT, 0)
window.swapBuffers(w)
window.pollEvents()
end
window.destroy(w)
gl.Terminate()
|
