Add new texture extension methods

Author: adamgraham

Runtime/Extensions/TextureExtensions.cs

@@ -0,0 +1,116 @@
+using UnityEngine;
+
+namespace Zigurous.Graphics
+{
+    /// <summary>
+    /// Extension methods for textures.
+    /// </summary>
+    public static class TextureExtensions
+    {
+        /// <summary>
+        /// Maps the UV coordinates in the range [0..1] to pixel coordinates
+        /// in the range [0..width-1] and [0..height-1].
+        /// </summary>
+        /// <param name="texture">The texture to get the pixel coordinates from.</param>
+        /// <param name="u">The UV coordinate in the x-axis.</param>
+        /// <param name="v">The UV coordinate in the y-axis.</param>
+        /// <param name="px">The output pixel coordinate in the x-axis.</param>
+        /// <param name="py">The output pixel coordinate in the y-axis.</param>
+        public static void GetPixelCoordinates(this Texture2D texture, float u, float v, out int px, out int py)
+        {
+            px = (int)Mathf.Lerp(0, texture.width - 1, u);
+            py = (int)Mathf.Lerp(0, texture.height - 1, v);
+        }
+
+        /// <summary>
+        /// Maps the pixel coordinates in the range [0..width-1] and
+        /// [0..height-1] to UV coordinates in the range [0..1].
+        /// </summary>
+        /// <param name="texture">The texture to get the UV coordinates from.</param>
+        /// <param name="px">The pixel coordinate in the x-axis.</param>
+        /// <param name="py">The pixel coordinate in the y-axis.</param>
+        /// <param name="u">The output UV coordinate in the x-axis.</param>
+        /// <param name="v">The output UV coordinate in the y-axis.</param>
+        public static void GetUVCoordinates(this Texture2D texture, int px, int py, out float u, out float v)
+        {
+            u = Mathf.InverseLerp(0, texture.width - 1, px);
+            v = Mathf.InverseLerp(0, texture.height - 1, py);
+        }
+
+        /// <summarys>
+        /// Gets the pixel color at the specified UV coordinates.
+        /// </summary>
+        /// <param name="texture">The texture to sample from.</param>
+        /// <param name="u">The UV coordinate in the x-axis.</param>
+        /// <param name="v">The UV coordinate in the y-axis.</param>
+        /// <returns>The pixel color.</returns>
+        public static Color Sample(this Texture2D texture, float u, float v)
+        {
+            if (texture == null || texture.width == 0 || texture.height == 0) {
+                return Color.clear;
+            }
+
+            texture.GetPixelCoordinates(u, v, out int px, out int py);
+            return texture.GetPixel(px, py);
+        }
+
+        /// <summary>
+        /// Gets the pixel color at the UV coordinates calculated from a point
+        /// inside a rectangle.
+        /// </summary>
+        /// <param name="texture">The texture to sample from.</param>
+        /// <param name="rect">The rectangle to sample from.</param>
+        /// <param name="point">The point inside the rectangle.</param>
+        /// <returns>The pixel color.</returns>
+        public static Color Sample(this Texture2D texture, Rect rect, Vector2 point)
+        {
+            if (texture == null || texture.width == 0 || texture.height == 0) {
+                return Color.clear;
+            }
+
+            float u = Mathf.InverseLerp(rect.min.x, rect.max.x, point.x);
+            float v = Mathf.InverseLerp(rect.min.y, rect.max.y, point.y);
+
+            return Sample(texture, u, v);
+        }
+
+        /// <summary>
+        /// Gets the pixel color at the UV coordinates calculated from a
+        /// position inside a bounds. The position uses the x and z axis.
+        /// </summary>
+        /// <param name="texture">The texture to sample from.</param>
+        /// <param name="bounds">The bounds to sample from.</param>
+        /// <param name="position">The position inside the bounds.</param>
+        /// <returns>The pixel color.</returns>
+        public static Color Sample(this Texture2D texture, Bounds bounds, Vector3 position)
+        {
+            if (texture == null || texture.width == 0 || texture.height == 0) {
+                return Color.clear;
+            }
+
+            float u = Mathf.InverseLerp(bounds.min.x, bounds.max.x, position.x);
+            float v = Mathf.InverseLerp(bounds.min.z, bounds.max.z, position.z);
+
+            return Sample(texture, u, v);
+        }
+
+        /// <summary>
+        /// Sets every pixel in the texture to the specified color.
+        /// </summary>
+        /// <param name="texture">The texture to set the color of.</param>
+        /// <param name="color">The color to set the texture to.</param>
+        public static void SetColor(this Texture2D texture, Color32 color)
+        {
+            var colors = texture.GetRawTextureData<Color32>();
+            int length = colors.Length;
+
+            for (int i = 0; i < length; i++) {
+                colors[i] = color;
+            }
+
+            texture.Apply();
+        }
+
+    }
+
+}