add more model & shader examples

examples/shaders/texture_outline/main.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+func main() {
+	screenWidth := int32(800)
+	screenHeight := int32(450)
+
+	rl.InitWindow(screenWidth, screenHeight, "raylib [shaders] example - texture outline")
+
+	texture := rl.LoadTexture("gopher.png")
+
+	shader := rl.LoadShader("", "outline.fs")
+
+	cnt := rl.NewVector2(float32(screenWidth/2), float32(screenHeight/2))
+
+	outlineSize := []float32{2}
+	outlineColor := []float32{1, 0, 0, 1}
+	textureSize := []float32{float32(texture.Width), float32(texture.Height)}
+
+	outlineSizeLoc := rl.GetShaderLocation(shader, "outlineSize")
+	outlineColorLoc := rl.GetShaderLocation(shader, "outlineColor")
+	textureSizeLoc := rl.GetShaderLocation(shader, "textureSize")
+
+	rl.SetShaderValue(shader, outlineSizeLoc, outlineSize, rl.ShaderUniformFloat)
+	rl.SetShaderValue(shader, outlineColorLoc, outlineColor, rl.ShaderUniformVec4)
+	rl.SetShaderValue(shader, textureSizeLoc, textureSize, rl.ShaderUniformVec2)
+
+	rl.SetTargetFPS(60)
+
+	for !rl.WindowShouldClose() {
+
+		if rl.IsKeyPressed(rl.KeyUp) {
+			outlineSize[0]++
+		} else if rl.IsKeyPressed(rl.KeyDown) {
+			outlineSize[0]--
+			if outlineSize[0] < 1 {
+				outlineSize[0] = 1
+			}
+		}
+
+		rl.SetShaderValue(shader, outlineSizeLoc, outlineSize, rl.ShaderUniformFloat)
+
+		rl.BeginDrawing()
+
+		rl.ClearBackground(rl.RayWhite)
+
+		rl.BeginShaderMode(shader)
+
+		rl.DrawTexture(texture, int32(cnt.X)-texture.Width/2, int32(cnt.Y)-texture.Height/2, rl.White)
+
+		rl.EndShaderMode()
+
+		rl.DrawText("UP/DOWN ARROW KEYS INCREASE OUTLINE THICKNESS", 10, 10, 10, rl.Black)
+
+		rl.EndDrawing()
+	}
+
+	rl.UnloadShader(shader)
+	rl.UnloadTexture(texture)
+
+	rl.CloseWindow()
+}

examples/shaders/texture_outline/outline.fs

@@ -0,0 +1,35 @@
+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+uniform vec2 textureSize;
+uniform float outlineSize;
+uniform vec4 outlineColor;
+
+// Output fragment color
+out vec4 finalColor;
+
+void main()
+{
+    vec4 texel = texture(texture0, fragTexCoord);   // Get texel color
+    vec2 texelScale = vec2(0.0);
+    texelScale.x = outlineSize/textureSize.x;
+    texelScale.y = outlineSize/textureSize.y;
+
+    // We sample four corner texels, but only for the alpha channel (this is for the outline)
+    vec4 corners = vec4(0.0);
+    corners.x = texture(texture0, fragTexCoord + vec2(texelScale.x, texelScale.y)).a;
+    corners.y = texture(texture0, fragTexCoord + vec2(texelScale.x, -texelScale.y)).a;
+    corners.z = texture(texture0, fragTexCoord + vec2(-texelScale.x, texelScale.y)).a;
+    corners.w = texture(texture0, fragTexCoord + vec2(-texelScale.x, -texelScale.y)).a;
+
+    float outline = min(dot(corners, vec4(1.0)), 1.0);
+    vec4 color = mix(vec4(0.0), outlineColor, outline);
+    finalColor = mix(color, texel, texel.a);
+}