cscの作法 その617

概要

cscの作法、調べてみた。
opentkでshadertoy、やってみた。
iResolution、iGlobalTime、iFrameを導入。

写真

サンプルコード

using System;
using System.Drawing;
using OpenTK;
using OpenTK.Graphics;
using OpenTK.Graphics.OpenGL4;

namespace App
{
	class Gwin: GameWindow {
		double counter = 0;
		private readonly float[] Vertices = {
			-1.0f, -1.0f, 0.0f,  -1.0f, 1.0f, 0.0f,  1.0f, 1.0f, 0.0f,
			-1.0f, -1.0f, 0.0f,   1.0f, -1.0f, 0.0f, 1.0f, 1.0f, 0.0f,
		};
		private int[] VertexBufferObjects = new int[1];
		private int[] VertexArrayObjects = new int[1];
		private int VertexShader;
		private int FragmentShader;
		private int Program;
		private int PositionLocation;
		private readonly string VertexShaderSourceCode = @"#version 330 core
layout(location = 0) in vec3 InPosition;
void main() {
	gl_Position = vec4(InPosition, 1.0);
}
";
		private readonly string FragmentShaderSourceCode = @"#version 330 core
out vec4 FragColor;
uniform vec2 iResolution;
uniform float iGlobalTime;
uniform int iFrame;
#define PI 			3.14159265359
#define TWOPI 		6.28318530718
float linearstep(float edge0, float edge1, float x) {
	float t = (x - edge0) / (edge1 - edge0);
	return clamp(t, 0.0, 1.0);
}
float smootherstep(float edge0, float edge1, float x) {
	float t = (x - edge0) / (edge1 - edge0);
	float t1 = t * t * t * (t * (t * 6. - 15.) + 10.);
	return clamp(t1, 0.0, 1.0);
}
void plot(vec2 r, float y, float lineThickness, vec3 color, inout vec3 pixel) {
	if (abs(y - r.y) < lineThickness)
		pixel = color;
}
void mainImage(out vec4 fragColor, in vec2 fragCoord) {
	vec2 r = 2.0 * vec2(fragCoord.xy - 0.5 * iResolution.xy) / iResolution.y;
	vec3 bgCol = vec3(1.0);
	vec3 axesCol = vec3(0.0, 0.0, 1.0);
	vec3 gridCol = vec3(0.5);
	vec3 col1 = vec3(0.841, 0.582, 0.594);
	vec3 col2 = vec3(0.884, 0.850, 0.648);
	vec3 col3 = vec3(0.348, 0.555, 0.641);
	vec3 pixel = bgCol;
	const float tickWidth = 0.1;
	for (float i = -2.0; i < 2.0; i += tickWidth)
	{
		if (abs(r.x - i) < 0.004)
			pixel = gridCol;
		if (abs(r.y - i) < 0.004)
			pixel = gridCol;
	}
	if (abs(r.x) < 0.006)
		pixel = axesCol;
	if (abs(r.y) < 0.007)
		pixel = axesCol;
	float x = r.x;
	float y = r.y;
	if (abs(2. * x + .5 - y) < 0.02)
		pixel = col1;
	if (abs(r.x * r.x - 0.2 - y) < 0.01)
		pixel = col1;
	if (abs(sin(PI * r.x) - y) < 0.02)
		pixel = col1;
	if (abs(0.25 * step(0.0, x) + 0.6 - y) < 0.01)
		pixel = col3;
	if (abs(0.25 * linearstep(-0.5, 0.5, x) + 0.1 - y) < 0.01)
		pixel = col3;
	if (abs(0.25 * smoothstep(-0.5, 0.5, x) - 0.4 - y) < 0.01)
		pixel = col3;
	if (abs(0.25 * smootherstep(-0.5, 0.5, x) - 0.9 - y) < 0.01)
		pixel = col3;
	plot(r, 0.5 * clamp(sin(TWOPI * x), 0.0, 1.0) - 0.7, 0.015, col2, pixel);
	plot(r, 0.6 * exp(-10.0 * (x + 0.8) * (x + 0.8)) - 0.1, 0.015, col2, pixel);
	fragColor = vec4(pixel, 1.0);
}
void main(void) {
	vec4 color = vec4(1.0, 0.0, 0.0, 1.0);
	mainImage(color, gl_FragCoord.xy);
	color.w = 1.0;
	FragColor = color;
}
";
		public Gwin(int width, int height, GraphicsMode mode, string title): base(width, height, mode, title) {
			this.VSync = VSyncMode.On;
			InitializeBuffer();
			InitializeShader();
			InitializeProgram();
			InitializeVertexArrayObject();
		}
		private void InitializeBuffer() {
			GL.GenBuffers(1, VertexBufferObjects);
			GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObjects[0]);
			GL.BufferData(BufferTarget.ArrayBuffer, 4 * 18, Vertices, BufferUsageHint.StaticDraw);
			GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
		}
		private void InitializeShader() {
			VertexShader = CreateShader(ShaderType.VertexShader, VertexShaderSourceCode);
			FragmentShader = CreateShader(ShaderType.FragmentShader, FragmentShaderSourceCode);
		}
		private int CreateShader(ShaderType shaderType, string sourceCode) {
			int shader = GL.CreateShader(shaderType);
			GL.ShaderSource(shader, sourceCode);
			GL.CompileShader(shader);
			string log = GL.GetShaderInfoLog(shader);
			return shader;
		}
		private void InitializeProgram() {
			Program = GL.CreateProgram();
			GL.AttachShader(Program, VertexShader);
			GL.AttachShader(Program, FragmentShader);
			GL.LinkProgram(Program);
			GL.UseProgram(Program);
			PositionLocation = GL.GetAttribLocation(Program, "InPosition");
			GL.UseProgram(0);
		}
		private void InitializeVertexArrayObject() {
			GL.GenVertexArrays(1, VertexArrayObjects);
			GL.BindVertexArray(VertexArrayObjects[0]);
			GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObjects[0]);
			GL.EnableVertexAttribArray(PositionLocation);
			GL.VertexAttribPointer(PositionLocation, 3, VertexAttribPointerType.Float, false, 12, 0);
			GL.EnableVertexAttribArray(0);
			GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
			GL.BindVertexArray(0);
		}
		protected override void OnUpdateFrame(FrameEventArgs args) {
			base.OnUpdateFrame(args);
		}
		protected override void OnResize(EventArgs e) {
			GL.Viewport(0, 0, Width, Height);
		}
		protected override void OnUnload(EventArgs e) {
			base.OnUnload(e);
			GL.DeleteVertexArrays(1, VertexArrayObjects);
			GL.DeleteBuffers(1, VertexBufferObjects);
			GL.DeleteProgram(Program);
		}
		protected override void OnRenderFrame(FrameEventArgs e) {
			base.OnRenderFrame(e);
			counter += e.Time;
			GL.Clear(ClearBufferMask.ColorBufferBit);
			GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObjects[0]);
			GL.BindVertexArray(VertexArrayObjects[0]);
			GL.UseProgram(Program);
			int resLoc = GL.GetUniformLocation(Program, "iResolution");
			GL.Uniform2(resLoc, new Vector2(Width, Height));
			int timeLoc = GL.GetUniformLocation(Program, "iGlobalTime");
			GL.Uniform1(timeLoc, (float) counter);
			int frameLoc = GL.GetUniformLocation(Program, "iFrame");
			GL.Uniform1(frameLoc, (int) (counter * 60));
			GL.DrawArrays(PrimitiveType.Triangles, 0, 3);
			GL.DrawArrays(PrimitiveType.Triangles, 3, 3);
			this.SwapBuffers();
		}
	}
	class Program {
		static void Main(string[] args) {
			Gwin window = new Gwin(500, 500, OpenTK.Graphics.GraphicsMode.Default, "Test");
			window.Run();
		}
	}
}

以上。