Initial prototype of paint clipping.

Paint clipping is a possible future feature to assist players building in cluttered areas of a park by controlling which map elements and sprites are rendered, providing a clearer view for construction, inspection, etc.

Only clip height is supported in this prototype.

Map elements are clipped according to the map element base height (meaning *all* scenery on that map element is currently clipped with it).

Sprites are clipped according to their z value being within the "sprite volume" of any non-clipped map element (which means below clip height + 2).

Control is only provided through the console in this prototype - use the command: set paint_clip_height _value_

To turn clipping off use the command: set paint_clip_height 255

Clip heights are limited to multiples of two to coincide with the native heights of map elements.

Command "get paint_clip_height" prints the clip height as a raw value as well as the equivalent height in ft and m as used when displaying heights in-game.

At this time only painting of the main viewport is affected. There is no change to any input control handling.

src/openrct2/interface/viewport.c

@@ -730,7 +730,7 @@ static void viewport_paint_column(rct_drawpixelinfo * dpi, uint32 viewFlags)
 {
 	gCurrentViewportFlags = viewFlags;
 
-	if (viewFlags & (VIEWPORT_FLAG_HIDE_VERTICAL | VIEWPORT_FLAG_HIDE_BASE | VIEWPORT_FLAG_UNDERGROUND_INSIDE)) {
+	if (viewFlags & (VIEWPORT_FLAG_HIDE_VERTICAL | VIEWPORT_FLAG_HIDE_BASE | VIEWPORT_FLAG_UNDERGROUND_INSIDE | VIEWPORT_FLAG_PAINT_CLIP_TO_HEIGHT)) {
 		uint8 colour = 10;
 		if (viewFlags & VIEWPORT_FLAG_INVISIBLE_SPRITES) {
 			colour = 0;

src/openrct2/interface/viewport.h

@@ -39,7 +39,8 @@ enum {
 	VIEWPORT_FLAG_HIDE_VERTICAL = (1 << 13),
 	VIEWPORT_FLAG_INVISIBLE_SPRITES = (1 << 14),
 	VIEWPORT_FLAG_15 = (1 << 15),
-	VIEWPORT_FLAG_SEETHROUGH_PATHS = (1 << 16)
+	VIEWPORT_FLAG_SEETHROUGH_PATHS = (1 << 16),
+	VIEWPORT_FLAG_PAINT_CLIP_TO_HEIGHT = (1 << 17) // zax
 };
 
 enum {

src/openrct2/paint/map_element/map_element.c

@@ -167,6 +167,13 @@ static void sub_68B3FB(sint32 x, sint32 y)
 	rct_map_element* map_element = map_get_first_element_at(x >> 5, y >> 5);
 	uint8 rotation = get_current_rotation();
 
+	/* Check if the first (lowest) map_element is below the clip
+	 * height. */
+	if ((gCurrentViewportFlags & VIEWPORT_FLAG_PAINT_CLIP_TO_HEIGHT) && (map_element->base_height > gClipHeight)) {
+		blank_tiles_paint(x, y);
+		return;
+	}
+
 	sint32 dx = 0;
 	switch (rotation) {
 	case 0:
@@ -240,6 +247,9 @@ static void sub_68B3FB(sint32 x, sint32 y)
 	gUnk9DE56C = y;
 	gDidPassSurface = false;
 	do {
+		// Only paint map_elements below the clip height.
+		if ((gCurrentViewportFlags & VIEWPORT_FLAG_PAINT_CLIP_TO_HEIGHT) && (map_element->base_height > gClipHeight)) break;
+
 		sint32 direction = (map_element->type + rotation) & MAP_ELEMENT_DIRECTION_MASK;
 		sint32 height = map_element->base_height * 8;
 
@@ -309,6 +319,9 @@ static void sub_68B3FB(sint32 x, sint32 y)
 				imageColourFlats = 0b111011 << 19 | 0x40000000;
 			}
 
+			// Only draw supports above the clipping height.
+			if ((gCurrentViewportFlags & VIEWPORT_FLAG_PAINT_CLIP_TO_HEIGHT) && (segmentHeight > gClipHeight)) continue;
+
 			sint32 xOffset = sy * 10;
 			sint32 yOffset = -22 + sx * 10;
 			paint_struct * ps = sub_98197C(5504 | imageColourFlats, xOffset, yOffset, 10, 10, 1, segmentHeight, xOffset + 1, yOffset + 16, segmentHeight, get_current_rotation());

src/openrct2/paint/paint.c

@@ -23,6 +23,9 @@
 #include "sprite/sprite.h"
 #include "supports.h"
 
+// zax: globals for paint clipping height
+uint8 gClipHeight = 255;
+
 const uint32 construction_markers[] = {
 	COLOUR_DARK_GREEN << 19 | COLOUR_GREY << 24 | IMAGE_TYPE_REMAP, // White
 	PALETTE_DARKEN_2 << 19 | IMAGE_TYPE_TRANSPARENT, // Translucent
@@ -199,6 +202,7 @@ static paint_struct * sub_9819_c(uint32 image_id, rct_xyz16 offset, rct_xyz16 bo
 	ps->map_x = gPaintMapPosition.x;
 	ps->map_y = gPaintMapPosition.y;
 	ps->mapElement = g_currently_drawn_item;
+
 	return ps;
 }
 
@@ -366,7 +370,6 @@ paint_struct * sub_98197C(
 	sint16 bound_box_offset_x, sint16 bound_box_offset_y, sint16 bound_box_offset_z,
 	uint32 rotation
 ) {
-
 	g_ps_F1AD28 = 0;
 	g_aps_F1AD2C = NULL;
 

src/openrct2/paint/paint.h

@@ -23,6 +23,9 @@
 #include "../interface/colour.h"
 #include "../drawing/drawing.h"
 
+// zax: Global paint clipping height.
+extern uint8 gClipHeight;
+
 typedef struct attached_paint_struct attached_paint_struct;
 typedef struct paint_struct paint_struct;
 typedef union paint_entry paint_entry;

src/openrct2/paint/sprite/sprite.c

@@ -21,6 +21,7 @@
 #include "../../ride/ride_data.h"
 #include "../../interface/viewport.h"
 #include "../../ride/vehicle_paint.h"
+#include "../../localisation/localisation.h" // zax
 
 /**
  * Paint Quadrant
@@ -45,6 +46,11 @@ void sprite_paint_setup(const uint16 eax, const uint16 ecx) {
 
 	for (rct_sprite* spr = get_sprite(sprite_idx); sprite_idx != SPRITE_INDEX_NULL; sprite_idx = spr->unknown.next_in_quadrant) {
 		spr = get_sprite(sprite_idx);
+
+		// zax: Only paint sprites that are below the clip height.
+		// Here converting from land/path/etc height scale to pixel height scale.
+		if ((gCurrentViewportFlags & VIEWPORT_FLAG_PAINT_CLIP_TO_HEIGHT) && (spr->unknown.z >= ((gClipHeight+2) * 8))) continue;
+
 		dpi = unk_140E9A8;
 
 		if (dpi->y + dpi->height <= spr->unknown.sprite_top) continue;