Use RL_QUADS/RL_TRIANGLES for single-pixel drawing (#2750)

Addresses problem mentioned in
https://github.com/raysan5/raylib/issues/2744#issuecomment-1273568263
(in short: when drawing pixels using DrawPixel{,V} in camera mode,
upscaled pixel becomes a line instead of bigger pixel)

src/rshapes.c

@@ -104,21 +104,50 @@ void SetShapesTexture(Texture2D texture, Rectangle source)
 // Draw a pixel
 void DrawPixel(int posX, int posY, Color color)
 {
-    rlBegin(RL_LINES);
-        rlColor4ub(color.r, color.g, color.b, color.a);
-        rlVertex2f(posX, posY);
-        rlVertex2f(posX + 1, posY + 1);
-    rlEnd();
+  DrawPixelV((Vector2){ posX, posY }, color);
 }
 
 // Draw a pixel (Vector version)
 void DrawPixelV(Vector2 position, Color color)
 {
-    rlBegin(RL_LINES);
+#if defined(SUPPORT_QUADS_DRAW_MODE)
+    rlSetTexture(texShapes.id);
+
+    rlBegin(RL_QUADS);
+
+        rlNormal3f(0.0f, 0.0f, 1.0f);
+        rlColor4ub(color.r, color.g, color.b, color.a);
+
+        rlTexCoord2f(texShapesRec.x/texShapes.width, texShapesRec.y/texShapes.height);
+        rlVertex2f(position.x, position.y);
+
+        rlTexCoord2f(texShapesRec.x/texShapes.width, (texShapesRec.y + texShapesRec.height)/texShapes.height);
+        rlVertex2f(position.x, position.y + 1);
+
+        rlTexCoord2f((texShapesRec.x + texShapesRec.width)/texShapes.width, (texShapesRec.y + texShapesRec.height)/texShapes.height);
+        rlVertex2f(position.x + 1, position.y + 1);
+
+        rlTexCoord2f((texShapesRec.x + texShapesRec.width)/texShapes.width, texShapesRec.y/texShapes.height);
+        rlVertex2f(position.x + 1, position.y);
+
+    rlEnd();
+
+    rlSetTexture(0);
+#else
+    rlBegin(RL_TRIANGLES);
+
         rlColor4ub(color.r, color.g, color.b, color.a);
+
         rlVertex2f(position.x, position.y);
-        rlVertex2f(position.x + 1.0f, position.y + 1.0f);
+        rlVertex2f(position.x, position.y + 1);
+        rlVertex2f(position.x + 1, position.y);
+
+        rlVertex2f(position.x + 1, position.y);
+        rlVertex2f(position.x, position.y + 1);
+        rlVertex2f(position.x + 1, position.y + 1);
+
     rlEnd();
+#endif
 }
 
 // Draw a line