split platformer out of 2d so 2d is only camera and animation

7 files changed, 168 insertions, 110 deletions

diff --git a/README.md b/README.md
index b0923b2..9a8da19 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,8 @@ The engine modules are a `.h` and a `.c` pair, they depend on each other a bit,
 | font | konfont |
 | toml | kontoml |
 | tile | tilemaps and sprite sheets |
-| 2d | platformer body with coyote time and jump buffering, a scrolling camera, frame animation (adds tile) |
+| 2d | what any 2D game needs: a scrolling camera, frame animation, drawing frames of a sprite sheet |
+| platformer | a box that runs and jumps through a tilemap, with coyote time and jump buffering (adds tile) |
 | 3d | first person kit: mouse look body, walls from a tilemap, editable hill terrain (adds tile) |
 | sector | maps made of rooms (vertices, floors, ceilings, walls) with entities like doors and buttons, in a text format |
 | world | one place to move bodies through sector maps, terrain, tilemaps and your own boxes, cylinders, spheres and planes (needs 3d, sector) |
diff --git a/build.sh b/build.sh
index 3512228..5d1c4f8 100755
--- a/build.sh
+++ b/build.sh
@@ -12,7 +12,7 @@ developer=0
 usage()
 {
 	echo "usage: build.sh [-d] [-D] [-p platform] [-m module,...] [-o objdir] [target ...]"
-	echo "modules:   font toml tile pack ui debug assets image audio mic model 2d 3d sector world"
+	echo "modules:   font toml tile pack ui debug assets image audio mic model 2d platformer 3d sector world"
 	echo "platforms: native linux bsd windows"
 	echo "targets:   all run clean tools pack examples"
 	exit 1
@@ -77,7 +77,7 @@ addobj()
 for m in $modules; do
 	DEFS="$DEFS -DKON_MODULE_$(echo "$m" | tr 'a-z' 'A-Z')"
 	case $m in
-	font|toml|tile|pack|ui|debug|2d|3d|sector|world) addobj "kon$m" ;;
+	font|toml|tile|pack|ui|debug|2d|platformer|3d|sector|world) addobj "kon$m" ;;
 	assets) addobj konassets ;;
 	model) addobj konmodel; addobj konassets ;;
 	image) addobj stb_image ;;
@@ -106,7 +106,7 @@ need()
 case " $modules " in *" debug "*) need font; need assets ;; esac
 case " $modules " in *" ui "*) need font ;; esac
 case " $modules " in *" world "*) need 3d; need sector; need tile ;; esac
-case " $modules " in *" 2d "*) need tile ;; esac
+case " $modules " in *" platformer "*) need tile ;; esac
 case " $modules " in *" 3d "*) need tile ;; esac
 case " $modules " in *" model "*) need assets ;; esac
 case " $DEFS " in *" -DKON_MODULE_ASSETS "*) need pack ;; esac
diff --git a/examples/platform.c b/examples/platform.c
index 1ac48fb..b6f65ea 100644
--- a/examples/platform.c
+++ b/examples/platform.c
@@ -1,7 +1,7 @@
 /*
  * platform: a box that runs and jumps around a tilemap with a camera that follows it, and a ray that follows the mouse
  *
- * build:  ./build.sh -d -m 2d,font obj/platform
+ * build:  ./build.sh -d -m 2d,platformer,font obj/platform
  * run:    obj/platform
  *
  * left and right or a and d run, space or up jumps. the line from the box to the mouse stops at the first solid tile
@@ -14,9 +14,10 @@
 #include "konprogram.h"
 #include "kontile.h"
 #include "kon2d.h"
+#include "konplatformer.h"
 
-#if !defined(KON_MODULE_2D) || !defined(KON_MODULE_TILE) || !defined(KON_MODULE_FONT)
-#error "build with: ./build.sh -d -m 2d,font obj/platform"
+#if !defined(KON_MODULE_2D) || !defined(KON_MODULE_PLATFORMER) || !defined(KON_MODULE_TILE) || !defined(KON_MODULE_FONT)
+#error "build with: ./build.sh -d -m 2d,platformer,font obj/platform"
 #endif
 
 #define TILE 16
diff --git a/kon/kon2d.c b/kon/kon2d.c
index 2cc9fdd..8ce56d8 100644
--- a/kon/kon2d.c
+++ b/kon/kon2d.c
@@ -27,72 +27,6 @@
 
 #include <math.h>
 
-#define STEP (1.0 / 120.0)
-#define MAX_FRAME 0.25
-
-/*** platformer ***/
-
-void kon_platformerInit(kon_platformer_t *p, kon_box2_t box)
-{
-	kon_platformer_t zero = {0};
-
-	*p = zero;
-	p->box = box;
-	p->runSpeed = 120.0f;
-	p->groundAccel = 18.0f;
-	p->airAccel = 8.0f;
-	p->gravity = 700.0f;
-	p->jumpSpeed = 260.0f;
-	p->jumpCut = 60.0f;
-	p->maxFall = 400.0f;
-	p->coyoteTime = 0.08f;
-	p->bufferTime = 0.1f;
-}
-
-int kon_platformerStep(kon_platformer_t *p, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, float dt)
-{
-	float run = (float)p->moveX * p->runSpeed;
-	float ease = (p->onGround ? p->groundAccel : p->airAccel) * dt;
-	int flags;
-
-	if (ease > 1.0f) ease = 1.0f;
-	p->velocity.x += (run - p->velocity.x) * ease;
-	p->velocity.y += p->gravity * dt;
-	if (p->velocity.y > p->maxFall) p->velocity.y = p->maxFall;
-
-	if (p->jumpHeld && !p->jumpWas) p->buffer = p->bufferTime;
-	p->jumpWas = p->jumpHeld;
-	if (p->buffer > 0.0f) p->buffer -= dt;
-	if (p->coyote > 0.0f) p->coyote -= dt;
-
-	if (p->buffer > 0.0f && p->coyote > 0.0f) {
-		p->velocity.y = -p->jumpSpeed;
-		p->buffer = 0.0f;
-		p->coyote = 0.0f;
-	}
-	if (!p->jumpHeld && p->velocity.y < -p->jumpCut) p->velocity.y = -p->jumpCut;
-
-	flags = kon_tilemapMove(map, &p->box, p->velocity.x * dt, p->velocity.y * dt, solid, solidCount);
-
-	if (flags & (KON_HIT_LEFT | KON_HIT_RIGHT)) p->velocity.x = 0.0f;
-	if (flags & (KON_HIT_UP | KON_HIT_DOWN)) p->velocity.y = 0.0f;
-	p->onGround = (flags & KON_HIT_DOWN) != 0;
-	if (p->onGround) p->coyote = p->coyoteTime;
-	return flags;
-}
-
-void kon_platformerUpdate(kon_platformer_t *p, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, double dt)
-{
-	if (!(dt > 0.0)) return;
-	if (dt > MAX_FRAME) dt = MAX_FRAME;
-
-	p->leftover += (float)dt;
-	while (p->leftover >= (float)STEP) {
-		kon_platformerStep(p, map, solid, solidCount, (float)STEP);
-		p->leftover -= (float)STEP;
-	}
-}
-
 /*** camera ***/
 
 static float clampAxis(float value, float view, float bounds)
diff --git a/kon/kon2d.h b/kon/kon2d.h
index 7a58dc6..fce4bb2 100644
--- a/kon/kon2d.h
+++ b/kon/kon2d.h
@@ -27,43 +27,6 @@
 #define KON2D_H
 
 #include "konsofren.h"
-#include "koncollide.h"
-#include "kontile.h"
-
-/*** platformer ***/
-
-/* a box that runs and jumps through a tilemap. the game sets moveX and jumpHeld every frame, calls kon_platformerUpdate and reads
-   box, velocity and onGround back. everything is in map pixels and seconds. kon_platformerInit fills in the tuning values,
-   change them afterwards as you like */
-typedef struct kon_platformer {
-	kon_box2_t box;
-	kon_vec2_t velocity;
-	int onGround;
-
-	int moveX; /* -1 left, 0 stand, 1 right */
-	int jumpHeld;
-
-	float runSpeed;
-	float groundAccel, airAccel; /* how fast velocity.x closes in on the run speed, per second */
-	float gravity;
-	float jumpSpeed;
-	float jumpCut; /* letting go of jump early slows the rise to this speed */
-	float maxFall;
-	float coyoteTime; /* seconds after leaving a ledge a jump still works */
-	float bufferTime; /* seconds before landing a jump press is remembered */
-
-	/* private */
-	float coyote, buffer, leftover;
-	int jumpWas;
-} kon_platformer_t;
-
-void kon_platformerInit(kon_platformer_t *p, kon_box2_t box);
-
-/* one step of dt seconds, dt should be small and steady. returns the KON_HIT_ flags of the move */
-int kon_platformerStep(kon_platformer_t *p, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, float dt);
-
-/* takes the frame time and runs steps of 1/120 of a second, so the jump feels the same at any frame rate */
-void kon_platformerUpdate(kon_platformer_t *p, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, double dt);
 
 /*** camera ***/
 
diff --git a/kon/konplatformer.c b/kon/konplatformer.c
new file mode 100644
index 0000000..9d22c67
--- /dev/null
+++ b/kon/konplatformer.c
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * konplatformer.c
+ *
+ * Copyright (c) 2026 KonAki
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "konplatformer.h"
+
+#define STEP (1.0 / 120.0)
+#define MAX_FRAME 0.25
+
+/*** platformer ***/
+
+void kon_platformerInit(kon_platformer_t *p, kon_box2_t box)
+{
+	kon_platformer_t zero = {0};
+
+	*p = zero;
+	p->box = box;
+	p->runSpeed = 120.0f;
+	p->groundAccel = 18.0f;
+	p->airAccel = 8.0f;
+	p->gravity = 700.0f;
+	p->jumpSpeed = 260.0f;
+	p->jumpCut = 60.0f;
+	p->maxFall = 400.0f;
+	p->coyoteTime = 0.08f;
+	p->bufferTime = 0.1f;
+}
+
+int kon_platformerStep(kon_platformer_t *p, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, float dt)
+{
+	float run = (float)p->moveX * p->runSpeed;
+	float ease = (p->onGround ? p->groundAccel : p->airAccel) * dt;
+	int flags;
+
+	if (ease > 1.0f) ease = 1.0f;
+	p->velocity.x += (run - p->velocity.x) * ease;
+	p->velocity.y += p->gravity * dt;
+	if (p->velocity.y > p->maxFall) p->velocity.y = p->maxFall;
+
+	if (p->jumpHeld && !p->jumpWas) p->buffer = p->bufferTime;
+	p->jumpWas = p->jumpHeld;
+	if (p->buffer > 0.0f) p->buffer -= dt;
+	if (p->coyote > 0.0f) p->coyote -= dt;
+
+	if (p->buffer > 0.0f && p->coyote > 0.0f) {
+		p->velocity.y = -p->jumpSpeed;
+		p->buffer = 0.0f;
+		p->coyote = 0.0f;
+	}
+	if (!p->jumpHeld && p->velocity.y < -p->jumpCut) p->velocity.y = -p->jumpCut;
+
+	flags = kon_tilemapMove(map, &p->box, p->velocity.x * dt, p->velocity.y * dt, solid, solidCount);
+
+	if (flags & (KON_HIT_LEFT | KON_HIT_RIGHT)) p->velocity.x = 0.0f;
+	if (flags & (KON_HIT_UP | KON_HIT_DOWN)) p->velocity.y = 0.0f;
+	p->onGround = (flags & KON_HIT_DOWN) != 0;
+	if (p->onGround) p->coyote = p->coyoteTime;
+	return flags;
+}
+
+void kon_platformerUpdate(kon_platformer_t *p, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, double dt)
+{
+	if (!(dt > 0.0)) return;
+	if (dt > MAX_FRAME) dt = MAX_FRAME;
+
+	p->leftover += (float)dt;
+	while (p->leftover >= (float)STEP) {
+		kon_platformerStep(p, map, solid, solidCount, (float)STEP);
+		p->leftover -= (float)STEP;
+	}
+}
diff --git a/kon/konplatformer.h b/kon/konplatformer.h
new file mode 100644
index 0000000..710f0e0
--- /dev/null
+++ b/kon/konplatformer.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * konplatformer.h
+ *
+ * Copyright (c) 2026 KonAki
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef KONPLATFORMER_H
+#define KONPLATFORMER_H
+
+#include "koncollide.h"
+#include "kontile.h"
+
+/*** platformer ***/
+
+/* a box that runs and jumps through a tilemap. the game sets moveX and jumpHeld every frame, calls kon_platformerUpdate and reads
+   box, velocity and onGround back. everything is in map pixels and seconds. kon_platformerInit fills in the tuning values,
+   change them afterwards as you like */
+typedef struct kon_platformer {
+	kon_box2_t box;
+	kon_vec2_t velocity;
+	int onGround;
+
+	int moveX; /* -1 left, 0 stand, 1 right */
+	int jumpHeld;
+
+	float runSpeed;
+	float groundAccel, airAccel; /* how fast velocity.x closes in on the run speed, per second */
+	float gravity;
+	float jumpSpeed;
+	float jumpCut; /* letting go of jump early slows the rise to this speed */
+	float maxFall;
+	float coyoteTime; /* seconds after leaving a ledge a jump still works */
+	float bufferTime; /* seconds before landing a jump press is remembered */
+
+	/* private */
+	float coyote, buffer, leftover;
+	int jumpWas;
+} kon_platformer_t;
+
+void kon_platformerInit(kon_platformer_t *p, kon_box2_t box);
+
+/* one step of dt seconds, dt should be small and steady. returns the KON_HIT_ flags of the move */
+int kon_platformerStep(kon_platformer_t *p, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, float dt);
+
+/* takes the frame time and runs steps of 1/120 of a second, so the jump feels the same at any frame rate */
+void kon_platformerUpdate(kon_platformer_t *p, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, double dt);
+
+#endif