Redesigned billboards - added rotation/pro functions (#1759)

* Redesigned billboards - added rotation/pro functions

* updated parameters

Co-authored-by: nobytesgiven <nobytesigiven@github.com>

src/models.c

@@ -2802,14 +2802,27 @@ void DrawBillboard(Camera camera, Texture2D texture, Vector3 center, float size,
 {
     Rectangle source = { 0.0f, 0.0f, (float)texture.width, (float)texture.height };
 
-    DrawBillboardRec(camera, texture, source, center, size, tint);
+    DrawBillboardRec(camera, texture, source, center, (Vector2){ size, size }, tint);
 }
 
 // Draw a billboard (part of a texture defined by a rectangle)
-void DrawBillboardRec(Camera camera, Texture2D texture, Rectangle source, Vector3 center, float size, Color tint)
+void DrawBillboardRec(Camera camera, Texture2D texture, Rectangle source, Vector3 center, Vector2 size, Color tint)
+{
+    DrawBillboardPro(camera, texture, source, center, size, Vector2Zero(), 0.0f, tint);
+}
+
+// Draw a billboard (part of a texture defined by a rectangle)
+void DrawBillboardEx(Camera camera, Texture2D texture, Vector3 center, Vector2 origin, float rotation, Vector2 size, Color tint)
+{
+	Rectangle source = { 0.0f, 0.0f, (float)texture.width, (float)texture.height };
+	
+	DrawBillboardPro(camera, texture, source, center, size, origin, rotation, tint);
+}
+
+void DrawBillboardPro(Camera camera, Texture2D texture, Rectangle source, Vector3 position, Vector2 size, Vector2 origin, float rotation, Color tint)
 {
     // NOTE: Billboard size will maintain source rectangle aspect ratio, size will represent billboard width
-    Vector2 sizeRatio = { size, size*(float)source.height/source.width };
+    Vector2 sizeRatio = { size.y, size.x*(float)source.height/source.width };
 	
     Matrix matView = MatrixLookAt(camera.position, camera.target, camera.up);
 
@@ -2818,23 +2831,59 @@ void DrawBillboardRec(Camera camera, Texture2D texture, Rectangle source, Vector
 
     // NOTE: Billboard locked on axis-Y
     Vector3 up = { 0.0f, 1.0f, 0.0f };
-/*
-    a-------b
-    |       |
-    |   *   |
-    |       |
-    d-------c
-*/
-    right = Vector3Scale(right, sizeRatio.x/2);
-    up = Vector3Scale(up, sizeRatio.y/2);
 
-    Vector3 p1 = Vector3Add(right, up);
+	Vector3 rightScaled = Vector3Scale(right, sizeRatio.x/2);
-    Vector3 p2 = Vector3Subtract(right, up);
+	Vector3 upScaled = Vector3Scale(up, sizeRatio.y/2);
 	
-    Vector3 a = Vector3Subtract(center, p2);
+    Vector3 p1 = Vector3Add(rightScaled, upScaled);
-    Vector3 b = Vector3Add(center, p1);
+    Vector3 p2 = Vector3Subtract(rightScaled, upScaled);
-    Vector3 c = Vector3Add(center, p2);
+
-    Vector3 d = Vector3Subtract(center, p1);
+    Vector3 topLeft = Vector3Scale(p2, -1);
+    Vector3 topRight = p1;
+    Vector3 bottomRight = p2;
+    Vector3 bottomLeft = Vector3Scale(p1, -1);
+	
+	if (rotation != 0.0f)
+	{	
+		float sinRotation = sinf(rotation*DEG2RAD);
+		float cosRotation = cosf(rotation*DEG2RAD);
+		
+		// NOTE: (-1, 1) is the range where origin.x, origin.y is inside the texture
+		float rotateAboutX = sizeRatio.x*origin.x/2;
+		float rotateAboutY = sizeRatio.y*origin.y/2;
+		
+		float xtvalue, ytvalue;
+		float rotatedX, rotatedY;
+		
+		xtvalue = Vector3DotProduct(right, topLeft) - rotateAboutX; // Project points to x and y coordinates on the billboard plane
+		ytvalue = Vector3DotProduct(up, topLeft) - rotateAboutY;
+		rotatedX = xtvalue*cosRotation - ytvalue*sinRotation + rotateAboutX; // Rotate about the point origin 
+		rotatedY = xtvalue*sinRotation + ytvalue*cosRotation + rotateAboutY;
+		topLeft = Vector3Add(Vector3Scale(up, rotatedY), Vector3Scale(right, rotatedX)); // Translate back to cartesian coordinates
+		
+		xtvalue = Vector3DotProduct(right, topRight) - rotateAboutX;
+		ytvalue = Vector3DotProduct(up, topRight) - rotateAboutY;
+		rotatedX = xtvalue*cosRotation - ytvalue*sinRotation + rotateAboutX;
+		rotatedY = xtvalue*sinRotation + ytvalue*cosRotation + rotateAboutY;
+		topRight = Vector3Add(Vector3Scale(up, rotatedY), Vector3Scale(right, rotatedX));
+
+		xtvalue = Vector3DotProduct(right, bottomRight) - rotateAboutX;
+		ytvalue = Vector3DotProduct(up, bottomRight) - rotateAboutY;
+		rotatedX = xtvalue*cosRotation - ytvalue*sinRotation + rotateAboutX;
+		rotatedY = xtvalue*sinRotation + ytvalue*cosRotation + rotateAboutY;
+		bottomRight = Vector3Add(Vector3Scale(up, rotatedY), Vector3Scale(right, rotatedX));
+		
+		xtvalue = Vector3DotProduct(right, bottomLeft)-rotateAboutX;
+		ytvalue = Vector3DotProduct(up, bottomLeft)-rotateAboutY;
+		rotatedX = xtvalue*cosRotation - ytvalue*sinRotation + rotateAboutX;
+		rotatedY = xtvalue*sinRotation + ytvalue*cosRotation + rotateAboutY;
+		bottomLeft = Vector3Add(Vector3Scale(up, rotatedY), Vector3Scale(right, rotatedX));
+	}
+	
+	topLeft = Vector3Add(topLeft, position); // Translate points to the draw center (position)
+	topRight = Vector3Add(topRight, position);
+	bottomRight = Vector3Add(bottomRight, position);
+	bottomLeft = Vector3Add(bottomLeft, position);
 	
     rlCheckRenderBatchLimit(4);
 
@@ -2845,19 +2894,19 @@ void DrawBillboardRec(Camera camera, Texture2D texture, Rectangle source, Vector
 
         // Bottom-left corner for texture and quad
         rlTexCoord2f((float)source.x/texture.width, (float)source.y/texture.height);
-        rlVertex3f(a.x, a.y, a.z);
+        rlVertex3f(topLeft.x, topLeft.y, topLeft.z);
 
         // Top-left corner for texture and quad
         rlTexCoord2f((float)source.x/texture.width, (float)(source.y + source.height)/texture.height);
-        rlVertex3f(d.x, d.y, d.z);
+        rlVertex3f(bottomLeft.x, bottomLeft.y, bottomLeft.z);
 
         // Top-right corner for texture and quad
         rlTexCoord2f((float)(source.x + source.width)/texture.width, (float)(source.y + source.height)/texture.height);
-        rlVertex3f(c.x, c.y, c.z);
+        rlVertex3f(bottomRight.x, bottomRight.y, bottomRight.z);
 
         // Bottom-right corner for texture and quad
         rlTexCoord2f((float)(source.x + source.width)/texture.width, (float)source.y/texture.height);
-        rlVertex3f(b.x, b.y, b.z);
+        rlVertex3f(topRight.x, topRight.y, topRight.z);
     rlEnd();
 
     rlSetTexture(0);	

src/raylib.h

@@ -1444,7 +1444,9 @@ RLAPI void DrawModelWires(Model model, Vector3 position, float scale, Color tint
 RLAPI void DrawModelWiresEx(Model model, Vector3 position, Vector3 rotationAxis, float rotationAngle, Vector3 scale, Color tint); // Draw a model wires (with texture if set) with extended parameters
 RLAPI void DrawBoundingBox(BoundingBox box, Color color);                                               // Draw bounding box (wires)
 RLAPI void DrawBillboard(Camera camera, Texture2D texture, Vector3 center, float size, Color tint);     // Draw a billboard texture
-RLAPI void DrawBillboardRec(Camera camera, Texture2D texture, Rectangle source, Vector3 center, float size, Color tint); // Draw a billboard texture defined by source
+RLAPI void DrawBillboardRec(Camera camera, Texture2D texture, Rectangle source, Vector3 center, Vector2 size, Color tint); // Draw a billboard texture defined by source
+RLAPI void DrawBillboardEx(Camera camera, Texture2D texture, Vector3 center, Vector2 origin, float rotation, Vector2 size, Color tint); // Draw a billboard texture defined by rotation 
+RLAPI void DrawBillboardPro(Camera camera, Texture2D texture, Rectangle source, Vector3 position, Vector2 size, Vector2 origin, float rotation, Color tint); // Draw a billboard texture defined by source and rotation
 
 // Collision detection functions
 RLAPI bool CheckCollisionSpheres(Vector3 center1, float radius1, Vector3 center2, float radius2);       // Detect collision between two spheres