[rtextures] add MixColors. a function to mix 2 colors together (#4310)

* added MixColors function to mix 2 colors together (Line 1428 raylib.h and Line 4995 in rtextures.c)

* renamed MixColors to ColorLerp (https://github.com/raysan5/raylib/pull/4310#issuecomment-2340121038)

* changed ColorLerp to be more like other functions

---------

Co-authored-by: CI <[email protected]>

src/raylib.h

@@ -1435,6 +1435,7 @@ RLAPI Color GetColor(unsigned int hexValue);                                // G
 RLAPI Color GetPixelColor(void *srcPtr, int format);                        // Get Color from a source pixel pointer of certain format
 RLAPI void SetPixelColor(void *dstPtr, Color color, int format);            // Set color formatted into destination pixel pointer
 RLAPI int GetPixelDataSize(int width, int height, int format);              // Get pixel data size in bytes for certain format
+RLAPI Color ColorLerp(Color color1, Color color2, float d);                 // Mix 2 Colors Together
 
 //------------------------------------------------------------------------------------
 // Font Loading and Text Drawing Functions (Module: text)

src/rtextures.c

@@ -4985,6 +4985,8 @@ Vector3 ColorToHSV(Color color)
     return hsv;
 }
 
+
+
 // Get a Color from HSV values
 // Implementation reference: https://en.wikipedia.org/wiki/HSL_and_HSV#Alternative_HSV_conversion
 // NOTE: Color->HSV->Color conversion will not yield exactly the same color due to rounding errors
@@ -5422,6 +5424,24 @@ int GetPixelDataSize(int width, int height, int format)
     return dataSize;
 }
 
+
+// Mix 2 Colors togehter. 
+// d = dominance. 0.5 for equal
+Color ColorLerp(Color color1, Color color2, float d) 
+{ 
+    Color newColor = { 0, 0, 0, 0 };
+    if (d < 0) {d=0.0f;}
+    else if(d>1) {d=1.0f;}
+
+    newColor.r = (unsigned char)((1.0f-d) * color1.r + d * color2.r);
+    newColor.g = (unsigned char)((1.0f-d) * color1.g + d * color2.g);
+    newColor.b = (unsigned char)((1.0f-d) * color1.b + d * color2.b);
+    newColor.a = (unsigned char)((1.0f-d) * color1.a + d * color2.a);
+
+    return newColor;
+}
+
+
 //----------------------------------------------------------------------------------
 // Module specific Functions Definition
 //----------------------------------------------------------------------------------