Fix rlsw persistent alpha blending state

Author: iztanos

src/external/rlsw.h

@@ -3909,7 +3909,6 @@ static void sw_immediate_set_color(const float color[4])
     RLSW.primitive.color[2] = color[2];
     RLSW.primitive.color[3] = color[3];
 
-    RLSW.primitive.hasColorAlpha |= (color[3] < 1.0f);
 }
 
 static void sw_immediate_set_texcoord(const float texcoord[2])
@@ -3948,6 +3947,9 @@ static void sw_immediate_push_vertex(const float position[4])
     for (int i = 0; i < 4; i++) vertex->color[i] = RLSW.primitive.color[i];
     for (int i = 0; i < 2; i++) vertex->texcoord[i] = RLSW.primitive.texcoord[i];
 
+    // Track whether any vertex in this primitive has alpha < 1.0
+    RLSW.primitive.hasColorAlpha |= (vertex->color[3] < 1.0f);
+
     // Immediate rendering of the primitive if the required number is reached
     if (RLSW.primitive.vertexCount == SW_PRIMITIVE_VERTEX_COUNT[RLSW.drawMode])
     {