New example : core/vr_simulator

examples/core/vr_simulator/distortion100.fs

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+#version 100
+
+precision mediump float;
+
+// Input vertex attributes (from vertex shader)
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// NOTE: Add here your custom variables
+uniform vec2 leftLensCenter;
+uniform vec2 rightLensCenter;
+uniform vec2 leftScreenCenter;
+uniform vec2 rightScreenCenter;
+uniform vec2 scale;
+uniform vec2 scaleIn;
+uniform vec4 deviceWarpParam;
+uniform vec4 chromaAbParam;
+
+void main()
+{
+    // Compute lens distortion
+    vec2 lensCenter = fragTexCoord.x < 0.5? leftLensCenter : rightLensCenter;
+    vec2 screenCenter = fragTexCoord.x < 0.5? leftScreenCenter : rightScreenCenter;
+    vec2 theta = (fragTexCoord - lensCenter)*scaleIn;
+    float rSq = theta.x*theta.x + theta.y*theta.y;
+    vec2 theta1 = theta*(deviceWarpParam.x + deviceWarpParam.y*rSq + deviceWarpParam.z*rSq*rSq + deviceWarpParam.w*rSq*rSq*rSq);
+    vec2 thetaBlue = theta1*(chromaAbParam.z + chromaAbParam.w*rSq);
+    vec2 tcBlue = lensCenter + scale*thetaBlue;
+
+    if (any(bvec2(clamp(tcBlue, screenCenter - vec2(0.25, 0.5), screenCenter + vec2(0.25, 0.5)) - tcBlue)))
+    {
+        // Set black fragment for everything outside the lens border
+        gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
+    }
+    else
+    {
+        // Compute color chroma aberration
+        float blue = texture2D(texture0, tcBlue).b;
+        vec2 tcGreen = lensCenter + scale*theta1;
+        float green = texture2D(texture0, tcGreen).g;
+
+        vec2 thetaRed = theta1*(chromaAbParam.x + chromaAbParam.y*rSq);
+        vec2 tcRed = lensCenter + scale*thetaRed;
+
+        float red = texture2D(texture0, tcRed).r;
+        gl_FragColor = vec4(red, green, blue, 1.0);
+    }
+}

examples/core/vr_simulator/distortion330.fs

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+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// Output fragment color
+out vec4 finalColor;
+
+// NOTE: Add here your custom variables
+uniform vec2 leftLensCenter = vec2(0.288, 0.5);
+uniform vec2 rightLensCenter = vec2(0.712, 0.5);
+uniform vec2 leftScreenCenter = vec2(0.25, 0.5);
+uniform vec2 rightScreenCenter = vec2(0.75, 0.5);
+uniform vec2 scale = vec2(0.25, 0.45);
+uniform vec2 scaleIn = vec2(4, 2.2222);
+uniform vec4 deviceWarpParam = vec4(1, 0.22, 0.24, 0);
+uniform vec4 chromaAbParam = vec4(0.996, -0.004, 1.014, 0.0);
+
+void main()
+{
+    // Compute lens distortion
+    vec2 lensCenter = fragTexCoord.x < 0.5? leftLensCenter : rightLensCenter;
+    vec2 screenCenter = fragTexCoord.x < 0.5? leftScreenCenter : rightScreenCenter;
+    vec2 theta = (fragTexCoord - lensCenter)*scaleIn;
+    float rSq = theta.x*theta.x + theta.y*theta.y;
+    vec2 theta1 = theta*(deviceWarpParam.x + deviceWarpParam.y*rSq + deviceWarpParam.z*rSq*rSq + deviceWarpParam.w*rSq*rSq*rSq);
+    vec2 thetaBlue = theta1*(chromaAbParam.z + chromaAbParam.w*rSq);
+    vec2 tcBlue = lensCenter + scale*thetaBlue;
+
+    if (any(bvec2(clamp(tcBlue, screenCenter - vec2(0.25, 0.5), screenCenter + vec2(0.25, 0.5)) - tcBlue)))
+    {
+        // Set black fragment for everything outside the lens border
+        finalColor = vec4(0.0, 0.0, 0.0, 1.0);
+    }
+    else
+    {
+        // Compute color chroma aberration
+        float blue = texture(texture0, tcBlue).b;
+        vec2 tcGreen = lensCenter + scale*theta1;
+        float green = texture(texture0, tcGreen).g;
+
+        vec2 thetaRed = theta1*(chromaAbParam.x + chromaAbParam.y*rSq);
+        vec2 tcRed = lensCenter + scale*thetaRed;
+
+        float red = texture(texture0, tcRed).r;
+        finalColor = vec4(red, green, blue, 1.0);
+    }
+}

examples/core/vr_simulator/main.go

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+/*******************************************************************************************
+*
+*   raylib [core] example - VR Simulator (Oculus Rift CV1 parameters)
+*
+*   Example originally created with raylib 2.5, last time updated with raylib 4.0
+*
+*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
+*   BSD-like license that allows static linking with closed source software
+*
+*   Copyright (c) 2017-2024 Ramon Santamaria (@raysan5)
+*
+********************************************************************************************/
+package main
+
+import (
+	"fmt"
+
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+const (
+	screenWidth  = 800
+	screenHeight = 450
+	glslVersion  = 330 // Desktop
+	// glslVersion = 100 // Android, web
+)
+
+func main() {
+	// NOTE: screenWidth/screenHeight should match VR device aspect ratio
+	rl.InitWindow(screenWidth, screenHeight, "raylib [core] example - vr simulator")
+
+	// VR device parameters definition
+	device := rl.VrDeviceInfo{
+		// Oculus Rift CV1 parameters for simulator
+		HResolution:            2160,     // Horizontal resolution in pixels
+		VResolution:            1200,     // Vertical resolution in pixels
+		HScreenSize:            0.133793, // Horizontal size in meters
+		VScreenSize:            0.0669,   // Vertical size in meters
+		EyeToScreenDistance:    0.041,    // Distance between eye and display in meters
+		LensSeparationDistance: 0.07,     // Lens separation distance in meters
+		InterpupillaryDistance: 0.07,     // IPD (distance between pupils) in meters
+
+		// NOTE: CV1 uses fresnel-hybrid-asymmetric lenses with specific compute shaders
+		// Following parameters are just an approximation to CV1 distortion stereo rendering
+
+		// Lens distortion constant parameters
+		LensDistortionValues: [4]float32{1.0, 0.22, 0.24, 0.0},
+		// Chromatic aberration correction parameters
+		ChromaAbCorrection: [4]float32{0.996, -0.004, 1.014, 0.0},
+	}
+
+	// Load VR stereo config for VR device parameters (Oculus Rift CV1 parameters)
+	config := rl.LoadVrStereoConfig(device)
+
+	// Distortion shader (uses device lens distortion and chroma)
+	fileName := fmt.Sprintf("distortion%d.fs", glslVersion)
+	distortion := rl.LoadShader("", fileName)
+
+	// Update distortion shader with lens and distortion-scale parameters
+	rl.SetShaderValue(distortion, rl.GetShaderLocation(distortion, "leftLensCenter"),
+		config.LeftLensCenter[:], rl.ShaderUniformVec2)
+	rl.SetShaderValue(distortion, rl.GetShaderLocation(distortion, "rightLensCenter"),
+		config.RightLensCenter[:], rl.ShaderUniformVec2)
+	rl.SetShaderValue(distortion, rl.GetShaderLocation(distortion, "leftScreenCenter"),
+		config.LeftScreenCenter[:], rl.ShaderUniformVec2)
+	rl.SetShaderValue(distortion, rl.GetShaderLocation(distortion, "rightScreenCenter"),
+		config.RightScreenCenter[:], rl.ShaderUniformVec2)
+
+	rl.SetShaderValue(distortion, rl.GetShaderLocation(distortion, "scale"),
+		config.Scale[:], rl.ShaderUniformVec2)
+	rl.SetShaderValue(distortion, rl.GetShaderLocation(distortion, "scaleIn"),
+		config.ScaleIn[:], rl.ShaderUniformVec2)
+	rl.SetShaderValue(distortion, rl.GetShaderLocation(distortion, "deviceWarpParam"),
+		device.LensDistortionValues[:], rl.ShaderUniformVec4)
+	rl.SetShaderValue(distortion, rl.GetShaderLocation(distortion, "chromaAbParam"),
+		device.ChromaAbCorrection[:], rl.ShaderUniformVec4)
+
+	// Initialize frame buffer for stereo rendering
+	// NOTE: Screen size should match HMD aspect ratio
+	target := rl.LoadRenderTexture(device.HResolution, device.VResolution)
+
+	// The target's height is flipped (in the source Rectangle), due to OpenGL reasons
+	sourceRec := rl.Rectangle{Width: float32(target.Texture.Width), Height: float32(-target.Texture.Height)}
+	destRec := rl.Rectangle{Width: float32(rl.GetScreenWidth()), Height: float32(rl.GetScreenHeight())}
+
+	// Define the camera to look into our 3d world
+
+	camera := rl.Camera{
+		Position:   rl.Vector3{X: 5, Y: 2, Z: 5},
+		Target:     rl.Vector3{Y: 2},
+		Up:         rl.Vector3{Y: 1},
+		Fovy:       60.0,
+		Projection: rl.CameraPerspective,
+	}
+
+	cubePosition := rl.Vector3{}
+
+	rl.DisableCursor()  // Limit cursor to relative movement inside the window
+	rl.SetTargetFPS(60) // Set our game to run at 60 frames-per-second
+
+	// Main game loop
+	for !rl.WindowShouldClose() { // Detect window close button or ESC key
+		// Update
+		rl.UpdateCamera(&camera, rl.CameraFirstPerson)
+
+		// Draw texture
+		rl.BeginTextureMode(target)
+		rl.ClearBackground(rl.RayWhite)
+		rl.BeginVrStereoMode(config)
+		rl.BeginMode3D(camera)
+
+		rl.DrawCube(cubePosition, 2.0, 2.0, 2.0, rl.Red)
+		rl.DrawCubeWires(cubePosition, 2.0, 2.0, 2.0, rl.Maroon)
+		rl.DrawGrid(40, 1.0)
+
+		rl.EndMode3D()
+		rl.EndVrStereoMode()
+		rl.EndTextureMode()
+
+		// Draw
+		rl.BeginDrawing()
+		rl.ClearBackground(rl.RayWhite)
+		rl.BeginShaderMode(distortion)
+		rl.DrawTexturePro(target.Texture, sourceRec, destRec, rl.Vector2{}, 0.0, rl.White)
+		rl.EndShaderMode()
+		rl.DrawFPS(10, 10)
+		rl.EndDrawing()
+	}
+
+	// De-Initialization
+	rl.UnloadVrStereoConfig(config) // Unload stereo config
+
+	rl.UnloadRenderTexture(target) // Unload stereo render fbo
+	rl.UnloadShader(distortion)    // Unload distortion shader
+
+	rl.CloseWindow() // Close window and OpenGL context
+}