本稿では、「ModernGL」を用いて、プロジェクションについて確認する。今回はかんたんに格子を作成したのち、カメラにプロジェクションを設定し、シーンがどのように描画されるのか確認する。
サンプルコード
GitHubはこちら
'''
Renders a blue triangle
'''
import numpy as np
import moderngl
from ported._example import Example
class PerspectiveProjection(Example):
gl_version = (3, 3)
title = "Perspective Projection"
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.prog = self.ctx.program(
vertex_shader='''
#version 330
in vec3 vert;
uniform float z_near;
uniform float z_far;
uniform float fovy;
uniform float ratio;
uniform vec3 center;
uniform vec3 eye;
uniform vec3 up;
mat4 perspective() {
float zmul = (-2.0 * z_near * z_far) / (z_far - z_near);
float ymul = 1.0 / tan(fovy * 3.14159265 / 360);
float xmul = ymul / ratio;
return mat4(
xmul, 0.0, 0.0, 0.0,
0.0, ymul, 0.0, 0.0,
0.0, 0.0, -1.0, -1.0,
0.0, 0.0, zmul, 0.0
);
}
mat4 lookat() {
vec3 forward = normalize(center - eye);
vec3 side = normalize(cross(forward, up));
vec3 upward = cross(side, forward);
return mat4(
side.x, upward.x, -forward.x, 0,
side.y, upward.y, -forward.y, 0,
side.z, upward.z, -forward.z, 0,
-dot(eye, side), -dot(eye, upward), dot(eye, forward), 1
);
}
void main() {
gl_Position = perspective() * lookat() * vec4(vert, 1.0);
}
''',
fragment_shader='''
#version 330
out vec4 color;
void main() {
color = vec4(0.04, 0.04, 0.04, 1.0);
}
''',
)
self.prog['z_near'].value = 0.1
self.prog['z_far'].value = 1000.0
self.prog['ratio'].value = self.aspect_ratio
self.prog['fovy'].value = 60
self.prog['eye'].value = (3, 3, 3)
self.prog['center'].value = (0, 0, 0)
self.prog['up'].value = (0, 0, 1)
grid = []
for i in range(65):
grid.append([i - 32, -32.0, 0.0, i - 32, 32.0, 0.0])
grid.append([-32.0, i - 32, 0.0, 32.0, i - 32, 0.0])
grid = np.array(grid, dtype='f4')
self.vbo = self.ctx.buffer(grid)
self.vao = self.ctx.simple_vertex_array(self.prog, self.vbo, 'vert')
def render(self, time: float, frame_time: float):
self.ctx.clear(1.0, 1.0, 1.0)
self.vao.render(moderngl.LINES, 65 * 4)
if __name__ == '__main__':
PerspectiveProjection.run()
