added gradient shaders to all primatives

primatives/triangle.cpp

@@ -157,6 +157,24 @@ namespace UwU {
             }
           }
           return;
+          
+        } else if (shader.shaderType == BUFFER) {
+          // Left-handed triangle case (midpoint is left of triangle)
+          if ((int16_t)midX < longBound[midY - topY]) {
+            for (uint16_t i = 0; i < height; i++) {
+              for (uint16_t x = (uint16_t)splitBound[i]; x <= (uint16_t)longBound[i]; x++) {
+                buffer.drawPixel(x, i + (uint16_t)topY, ShaderMethods::buffer(shader.u0, shader.v0, shader.buffer, x, i + topY));
+              }
+            }
+            // Right-handed triangle case (midpoint is right of triangle)
+          } else {
+            for (uint16_t i = 0; i < height; i++) {
+              for (uint16_t x = (uint16_t)longBound[i]; x <= (uint16_t)splitBound[i]; x++) {
+                buffer.drawPixel(x, i + (uint16_t)topY, ShaderMethods::buffer(shader.u0, shader.v0, shader.buffer, x, i + topY));
+              }
+            }
+          }
+          return;
         }
         return;
       }