clean up renders again

- improved readability a lot
- now applies overlays directly to underlying skin part *before* transforming

lib/renders.js

@@ -74,6 +74,7 @@ function flip(src) {
   return dst;
 }
 
+// skew for isometric perspective
 var skew_a = 26 / 45;    // 0.57777777
 var skew_b = skew_a * 2; // 1.15555555
 
@@ -89,92 +90,75 @@ exp.draw_model = function(rid, img, scale, overlay, is_body, callback) {
     var old_skin = skin.height === 32;
     var arm_width = 4;
 
-    var parts = {
-      head: {
-        front: resize(removeTransparency(getPart(skin, 8, 8, 8, 8, 1)), scale),
-        right: resize(removeTransparency(getPart(skin, 0, 8, 8, 8, 1)), scale),
-        top: resize(removeTransparency(getPart(skin, 8, 0, 8, 8, 1)), scale),
-      },
-      arm: {
-        right: {
-          front: resize(removeTransparency(getPart(skin, 44, 20, arm_width, 12, 1)), scale),
-          side: resize(removeTransparency(getPart(skin, 40, 20, 4, 12, 1)), scale),
-        },
-        left: {
-          front: null,
-        },
-      },
-      leg: {
-        right: {
-          front: resize(removeTransparency(getPart(skin, 4, 20, 4, 12, 1)), scale),
-          side: resize(removeTransparency(getPart(skin, 0, 20, 4, 12, 1)), scale),
-        },
-        left: {
-          front: null,
+    /* eslint-disable no-multi-spaces */
+    var head_top        = resize(removeTransparency(getPart(skin, 8, 0, 8, 8, 1)), scale);
+    var head_front      = resize(removeTransparency(getPart(skin, 8, 8, 8, 8, 1)), scale);
+    var head_right      = resize(removeTransparency(getPart(skin, 0, 8, 8, 8, 1)), scale);
+
+    var arm_right_top   = resize(removeTransparency(getPart(skin, 44, 16, arm_width, 4, 1)), scale);
+    var arm_right_front = resize(removeTransparency(getPart(skin, 44, 20, arm_width, 12, 1)), scale);
+    var arm_right_side  = resize(removeTransparency(getPart(skin, 40, 20, 4, 12, 1)), scale);
+
+    var arm_left_top    = old_skin ? flip(arm_right_top)   : resize(removeTransparency(getPart(skin, 36, 48, arm_width, 4, 1)), scale);
+    var arm_left_front  = old_skin ? flip(arm_right_front) : resize(removeTransparency(getPart(skin, 36, 52, arm_width, 12, 1)), scale);
+
+    var leg_right_front = resize(removeTransparency(getPart(skin, 4, 20, 4, 12, 1)), scale);
+    var leg_right_side  = resize(removeTransparency(getPart(skin, 0, 20, 4, 12, 1)), scale);
+
+    var leg_left_front  = old_skin ? flip(leg_right_front) : resize(removeTransparency(getPart(skin, 20, 52, 4, 12, 1)), scale);
+
+    var body_front      = resize(removeTransparency(getPart(skin, 20, 20, 8, 12, 1)), scale);
+    /* eslint-enable no-multi-spaces */
+
+    if (overlay) {
+      if (hasTransparency(getPart(skin, 32, 0, 32, 32, 1))) {
+        // render head overlay
+        head_top.getContext("2d").drawImage(getPart(skin, 40, 0, 8, 8, scale), 0, 0);
+        head_front.getContext("2d").drawImage(getPart(skin, 40, 8, 8, 8, scale), 0, 0);
+        head_right.getContext("2d").drawImage(getPart(skin, 32, 8, 8, 8, scale), 0, 0);
+      }
+
+      if (!old_skin) {
+        // See #117
+        // if MC-89760 gets fixed, we can (probably) simply check the whole skin for transparency
+
+        /* eslint-disable no-multi-spaces */
+        var body_region      = getPart(skin, 16, 32, 32, 16, 1);
+        var right_arm_region = getPart(skin, 48, 48, 16, 16, 1);
+        var left_arm_region  = getPart(skin, 40, 32, 16, 16, 1);
+        var right_leg_region = getPart(skin, 0, 32, 16, 16, 1);
+        var left_leg_region  = getPart(skin, 0, 48, 16, 16, 1);
+        /* eslint-enable no-multi-spaces */
+
+        if (hasTransparency(body_region)) {
+          // render body overlay
+          body_front.getContext("2d").drawImage(getPart(skin, 20, 36, 8, 12, scale), 0, 0);
         }
-      },
-      shoulder: {
-        right: resize(removeTransparency(getPart(skin, 44, 16, arm_width, 4, 1)), scale),
-        left: null,
-      },
-      body: resize(removeTransparency(getPart(skin, 20, 20, 8, 12, 1)), scale),
-    };
-    var overlays = {
-      head: {},
-      arm: {right: {}, left: {}},
-      leg: {right: {}, left: {}},
-      shoulder: {},
-      body: {},
-    };
-
-    // overlays
-    var render_head = overlay && hasTransparency(getPart(skin, 32, 0, 32, 32, 1));
-    var render_body;
-    var render_rleg;
-    var render_lleg;
-    var render_larm;
-    var render_rarm;
-
-    // head overlay is shifted 32px right
-    overlays.head.front = overlay && render_head && getPart(skin, 8 + 32, 8, 8, 8, scale);
-    overlays.head.right = overlay && render_head && getPart(skin, 0 + 32, 8, 8, 8, scale);
-    overlays.head.top = overlay && render_head && getPart(skin, 8 + 32, 0, 8, 8, scale);
-
-    if ( old_skin) {
-      parts.arm.left.front = flip(parts.arm.right.front);
-      parts.leg.left.front = flip(parts.leg.right.front);
-      parts.shoulder.left = flip(parts.shoulder.right);
-    } else {
-      // 1.8 skin - has separate left/right arms & legs
-      parts.arm.left.front = resize(removeTransparency(getPart(skin, 36, 52, arm_width, 12, 1)), scale);
-      parts.leg.left.front = resize(removeTransparency(getPart(skin, 20, 52, 4, 12, 1)), scale);
-      parts.shoulder.left = resize(removeTransparency(getPart(skin, 36, 48, arm_width, 4, 1)), scale);
-
-      // See #117
-      // if MC-89760 gets fixed, we can (probably) simply check the whole skin for transparency
-      render_body = overlay && hasTransparency(getPart(skin, 16, 32, 32, 16, 1));
-      render_rleg = overlay && hasTransparency(getPart(skin, 0, 32, 16, 16, 1));
-      render_lleg = overlay && hasTransparency(getPart(skin, 0, 48, 16, 16, 1));
-      render_larm = overlay && hasTransparency(getPart(skin, 40, 32, 16, 16, 1));
-      render_rarm = overlay && hasTransparency(getPart(skin, 48, 48, 16, 16, 1));
-
-      // body overlay is shifted 16px down
-      overlays.body.front = render_body && getPart(skin, 20, 20 + 16, 8, 12, scale);
-
-      // right arm overlay is shifted 16px down
-      overlays.arm.right.front = render_rarm && getPart(skin, 44, 20 + 16, arm_width, 12, scale);
-      overlays.arm.right.side = render_rarm && getPart(skin, 40, 20 + 16, 4, 12, scale);
-      overlays.shoulder.right = render_rarm && getPart(skin, 44, 16 + 16, arm_width, 4, scale);
-
-      // left arm overlay is shifted 16px right
-      overlays.arm.left.front = render_larm && getPart(skin, 36 + 16, 52, arm_width, 12, scale);
-      overlays.shoulder.left = render_larm && getPart(skin, 36 + 16, 48, arm_width, 4, scale);
-
-      // right leg overlay is shifted 16px down
-      overlays.leg.right.front = render_rleg && getPart(skin, 4, 20 + 16, 4, 12, scale);
-      overlays.leg.right.side = render_rleg && getPart(skin, 0, 20 + 16, 4, 12, scale);
-      // left leg overlay is shifted 16px left
-      overlays.leg.left.front = render_lleg && getPart(skin, 20 - 16, 52, 4, 12, scale);
+
+        if (hasTransparency(right_arm_region)) {
+          // render right arm overlay
+          arm_right_top.getContext("2d").drawImage(getPart(skin, 44, 32, arm_width, 4, scale), 0, 0);
+          arm_right_front.getContext("2d").drawImage(getPart(skin, 44, 36, arm_width, 12, scale), 0, 0);
+          arm_right_side.getContext("2d").drawImage(getPart(skin, 40, 36, 4, 12, scale), 0, 0);
+        }
+
+        if (hasTransparency(left_arm_region)) {
+          // render left arm overlay
+          arm_left_top.getContext("2d").drawImage(getPart(skin, 36 + 16, 48, arm_width, 4, scale), 0, 0);
+          arm_left_front.getContext("2d").drawImage(getPart(skin, 36 + 16, 52, arm_width, 12, scale), 0, 0);
+        }
+
+        if (hasTransparency(right_leg_region)) {
+          // render right leg overlay
+          leg_right_front.getContext("2d").drawImage(getPart(skin, 4, 36, 4, 12, scale), 0, 0);
+          leg_right_side.getContext("2d").drawImage(getPart(skin, 0, 36, 4, 12, scale), 0, 0);
+        }
+
+        if (hasTransparency(left_leg_region)) {
+          // render left leg overlay
+          leg_left_front.getContext("2d").drawImage(getPart(skin, 4, 52, 4, 12, scale), 0, 0);
+        }
+      }
     }
 
     var x = 0;
@@ -192,37 +176,11 @@ exp.draw_model = function(rid, img, scale, overlay, is_body, callback) {
       var frontc = front.getContext("2d");
       frontc.patternQuality = "fast";
 
-      frontc.drawImage(parts.arm.right.front, (4 - arm_width) * scale, 0 * scale, arm_width * scale, 12 * scale);
-      frontc.drawImage(parts.arm.left.front, 12 * scale, 0 * scale, arm_width * scale, 12 * scale);
-      frontc.drawImage(parts.body, 4 * scale, 0 * scale, 8 * scale, 12 * scale);
-      frontc.drawImage(parts.leg.right.front, 4 * scale, 12 * scale, 4 * scale, 12 * scale);
-      frontc.drawImage(parts.leg.left.front, 8 * scale, 12 * scale, 4 * scale, 12 * scale);
-
-      // front overlay
-      var fronto = new Canvas();
-      if (!old_skin) {
-        // pre-render front overlay onto separate canvas
-        fronto.width = scale * 16;
-        fronto.height = scale * 24;
-        var frontoc = fronto.getContext("2d");
-        frontoc.patternQuality = "fast";
-
-        if (render_rarm) {
-          frontoc.drawImage(overlays.arm.right.front, (4 - arm_width) * scale, 0 * scale, arm_width * scale, 12 * scale + 1);
-        }
-        if (render_larm) {
-          frontoc.drawImage(overlays.arm.left.front, 12 * scale, 0 * scale, arm_width * scale, 12 * scale + 1);
-        }
-        if (render_body) {
-          frontoc.drawImage(overlays.body.front, 4 * scale, 0 * scale, 8 * scale, 12 * scale);
-        }
-        if (render_rleg) {
-          frontoc.drawImage(overlays.leg.right.front, 4 * scale, 12 * scale, 4 * scale, 12 * scale);
-        }
-        if (render_lleg) {
-          frontoc.drawImage(overlays.leg.left.front, 8 * scale, 12 * scale, 4 * scale, 12 * scale);
-        }
-      }
+      frontc.drawImage(arm_right_front, (4 - arm_width) * scale, 0 * scale, arm_width * scale, 12 * scale);
+      frontc.drawImage(arm_left_front, 12 * scale, 0 * scale, arm_width * scale, 12 * scale);
+      frontc.drawImage(body_front, 4 * scale, 0 * scale, 8 * scale, 12 * scale);
+      frontc.drawImage(leg_right_front, 4 * scale, 12 * scale, 4 * scale, 12 * scale);
+      frontc.drawImage(leg_left_front, 8 * scale, 12 * scale, 4 * scale, 12 * scale);
 
 
       // top
@@ -230,47 +188,28 @@ exp.draw_model = function(rid, img, scale, overlay, is_body, callback) {
       y = scale * -arm_width;
       z = z_offset + scale * 8;
       ctx.setTransform(1, -skew_a, 1, skew_a, 0, 0);
-      ctx.drawImage(parts.shoulder.right, y - z - 0.5, x + z, parts.shoulder.right.width + 1, parts.shoulder.right.height + 1);
-      if (render_rarm) {
-        x -= 1;
-        ctx.drawImage(overlays.shoulder.right, y - z, x + z, overlays.shoulder.right.width + 2, overlays.shoulder.right.height + 2);
-      }
+      ctx.drawImage(arm_right_top, y - z - 0.5, x + z, arm_right_top.width + 1, arm_right_top.height + 1);
 
       y = scale * 8;
-      ctx.drawImage(parts.shoulder.left, y - z, x + z, parts.shoulder.left.width, parts.shoulder.left.height + 1);
-      if (render_larm) {
-        console.log(overlays.shoulder.left);
-        z += 0.5;
-        ctx.drawImage(overlays.shoulder.left, y - z, x + z, overlays.shoulder.left.width + 1, overlays.shoulder.left.height + 1);
-      }
+      ctx.drawImage(arm_left_top, y - z, x + z, arm_left_top.width, arm_left_top.height + 1);
 
       // right side
       ctx.setTransform(1, skew_a, 0, skew_b, 0, 0);
       x = x_offset + scale * 2;
       y = 0;
       z = z_offset + scale * 20;
-      ctx.drawImage(parts.leg.right.side, x + y, z - y, parts.leg.right.side.width, parts.leg.right.side.height);
-      if (render_rleg) {
-        ctx.drawImage(overlays.leg.right.side, x + y, z - y, overlays.leg.right.side.width, overlays.leg.right.side.height + 0.5);
-      }
+      ctx.drawImage(leg_right_side, x + y, z - y, leg_right_side.width, leg_right_side.height);
 
       x = x_offset + scale * 2;
       y = scale * -arm_width;
       z = z_offset + scale * 8;
-      ctx.drawImage(parts.arm.right.side, x + y, z - y - 0.5, parts.arm.right.side.width, parts.arm.right.side.height + 1);
-      if (render_rarm) {
-        z -= 1;
-        ctx.drawImage(overlays.arm.right.side, x + y, z - y, overlays.arm.right.side.width, overlays.arm.right.side.height + 2);
-      }
+      ctx.drawImage(arm_right_side, x + y, z - y - 0.5, arm_right_side.width, arm_right_side.height + 1);
 
       // front
       z = z_offset + scale * 12;
       y = 0;
       ctx.setTransform(1, -skew_a, 0, skew_b, 0, skew_a);
       ctx.drawImage(front, y + x, x + z - 0.5, front.width, front.height);
-      if (!old_skin) {
-        ctx.drawImage(fronto, y + x, x + z - 1, fronto.width, fronto.height + 1);
-      }
     }
 
     // head top
@@ -278,34 +217,21 @@ exp.draw_model = function(rid, img, scale, overlay, is_body, callback) {
     y = -0.5;
     z = z_offset;
     ctx.setTransform(1, -skew_a, 1, skew_a, 0, 0);
-    ctx.drawImage(parts.head.top, y - z, x + z, parts.head.top.width, parts.head.top.height + 1);
-    if (render_head) {
-      x -= 0.5;
-      z -= 0.5;
-      ctx.drawImage(overlays.head.top, y - z, x + z, overlays.head.top.width + 0.5, overlays.head.top.height + 1.5);
-    }
+    ctx.drawImage(head_top, y - z, x + z, head_top.width, head_top.height + 1);
 
     // head front
     x = x_offset + 8 * scale;
     y = 0;
     z = z_offset - 0.5;
     ctx.setTransform(1, -skew_a, 0, skew_b, 0, skew_a);
-    ctx.drawImage(parts.head.front, y + x, x + z, parts.head.front.width, parts.head.front.height);
-    if (render_head) {
-      z -= 1;
-      ctx.drawImage(overlays.head.front, y + x, x + z, overlays.head.front.width, overlays.head.front.height + 2);
-    }
+    ctx.drawImage(head_front, y + x, x + z, head_front.width, head_front.height);
 
     // head right
     x = x_offset;
     y = 0;
     z = z_offset;
     ctx.setTransform(1, skew_a, 0, skew_b, 0, 0);
-    ctx.drawImage(parts.head.right, x + y, z - y - 0.5, parts.head.right.width, parts.head.right.height + 1);
-    if (render_head) {
-      z -= 1;
-      ctx.drawImage(overlays.head.right, x + y, z - y - 0.5, overlays.head.right.width, overlays.head.right.height + 3);
-    }
+    ctx.drawImage(head_right, x + y, z - y - 0.5, head_right.width, head_right.height + 1);
 
     canvas.toBuffer(function(err, buf) {
       if (err) {