add 3d kit: first person body and tilemap level drawing

2 files changed, 296 insertions, 0 deletions

diff --git a/kon/kon3d.c b/kon/kon3d.c
new file mode 100644
index 0000000..8184039
--- /dev/null
+++ b/kon/kon3d.c
@@ -0,0 +1,212 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * kon3d.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 "kon3d.h"
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/*** private ***/
+
+static void kon_quad_(kon_framebuffer_t *fb, kon_mat4_t vp, const kon_material_t *material, const kon_light_t *light,
+		kon_vec3_t a, kon_vec3_t b, kon_vec3_t c, kon_vec3_t d, kon_vec3_t normal, kon_vec2_t uvA, kon_vec2_t uvC)
+{
+	kon_vertex_t va = { a, normal, uvA }, vb = { b, normal, KON_VEC2(uvC.x, uvA.y) };
+	kon_vertex_t vc = { c, normal, uvC }, vd = { d, normal, KON_VEC2(uvA.x, uvC.y) };
+
+	kon_drawTriangle3D(fb, vp, va, vb, vc, material, light, KON_RENDER_DEFAULT);
+	kon_drawTriangle3D(fb, vp, va, vc, vd, material, light, KON_RENDER_DEFAULT);
+}
+
+/* a wall face seen from its open side, left and right are the bottom corners as the viewer sees them */
+static void kon_wall_(kon_framebuffer_t *fb, kon_mat4_t vp, const kon_level3d_t *level, const kon_light_t *light,
+		kon_vec3_t left, kon_vec3_t right, kon_vec3_t normal)
+{
+	float h = level->wallHeight;
+	kon_vec3_t topRight = KON_VEC3(right.x, h, right.z), topLeft = KON_VEC3(left.x, h, left.z);
+
+	kon_quad_(fb, vp, level->wall, light, left, right, topRight, topLeft, normal, KON_VEC2(0, h), KON_VEC2(1, 0));
+}
+
+static int kon_open_(const kon_level3d_t *level, int column, int row)
+{
+	uint16_t id = kon_tilemapAt(level->map, column, row);
+
+	return id >= level->solidCount || !level->solid[id];
+}
+
+/*** body ***/
+
+void kon_fpInit(kon_fp_t *fp, const kon_tilemap_t *map, int column, int row)
+{
+	float size = 12.0f;
+
+	fp->eyeHeight = 0.6f;
+	fp->yaw = 0.0f;
+	fp->pitch = 0.0f;
+	fp->sensitivity = 0.0015f;
+	fp->speed = 2.5f;
+	fp->turnSpeed = 2.0f;
+	fp->fov = KON_DEG2RAD(60);
+	fp->forward = fp->strafe = fp->turn = 0;
+	fp->body = KON_BOX2(((float)column + 0.5f) * (float)map->tileWidth - size * 0.5f, ((float)row + 0.5f) * (float)map->tileHeight - size * 0.5f, size, size);
+}
+
+int kon_fpEvent(kon_fp_t *fp, kon_program_t *program, const kon_event_t *ev)
+{
+	int down;
+
+	if (ev->type == KON_EVENT_MOUSE_MOVE && kon_isMouseCaptured(program->window)) {
+		fp->yaw += (float)ev->mouseDX * fp->sensitivity;
+		fp->pitch -= (float)ev->mouseDY * fp->sensitivity;
+		if (fp->pitch > 1.2f) fp->pitch = 1.2f;
+		if (fp->pitch < -1.2f) fp->pitch = -1.2f;
+		return 1;
+	}
+	if (ev->type == KON_EVENT_MOUSE_DOWN && !kon_isMouseCaptured(program->window)) {
+		kon_setMouseCapture(program->window, true);
+		return 1;
+	}
+	if (ev->type == KON_EVENT_KEY_DOWN && ev->key == KON_KEY_TAB) {
+		kon_setMouseCapture(program->window, !kon_isMouseCaptured(program->window));
+		return 1;
+	}
+	if (ev->type != KON_EVENT_KEY_DOWN && ev->type != KON_EVENT_KEY_UP) return 0;
+	down = ev->type == KON_EVENT_KEY_DOWN;
+
+	switch (ev->key) {
+	case KON_KEY_W: case KON_KEY_UP: fp->forward = down ? 1 : (fp->forward > 0 ? 0 : fp->forward); break;
+	case KON_KEY_S: case KON_KEY_DOWN: fp->forward = down ? -1 : (fp->forward < 0 ? 0 : fp->forward); break;
+	case KON_KEY_D: fp->strafe = down ? 1 : (fp->strafe > 0 ? 0 : fp->strafe); break;
+	case KON_KEY_A: fp->strafe = down ? -1 : (fp->strafe < 0 ? 0 : fp->strafe); break;
+	case KON_KEY_RIGHT: fp->turn = down ? 1 : (fp->turn > 0 ? 0 : fp->turn); break;
+	case KON_KEY_LEFT: fp->turn = down ? -1 : (fp->turn < 0 ? 0 : fp->turn); break;
+	default: return 0;
+	}
+	return 1;
+}
+
+void kon_fpUpdate(kon_fp_t *fp, kon_program_t *program, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, double dt)
+{
+	float step = fp->speed * (float)dt * (float)map->tileWidth;
+	float fx = sinf(fp->yaw), fz = -cosf(fp->yaw);
+	float dx = (fx * (float)fp->forward - fz * (float)fp->strafe) * step;
+	float dz = (fz * (float)fp->forward + fx * (float)fp->strafe) * step;
+
+	if (kon_debugConsoleOpen(program->debug) && kon_isMouseCaptured(program->window)) kon_setMouseCapture(program->window, false);
+
+	fp->yaw += (float)fp->turn * fp->turnSpeed * (float)dt;
+	kon_tilemapMove(map, &fp->body, dx, dz, solid, solidCount);
+}
+
+kon_vec3_t kon_fpEye(const kon_fp_t *fp, const kon_tilemap_t *map)
+{
+	return KON_VEC3((fp->body.x + fp->body.w * 0.5f) / (float)map->tileWidth, fp->eyeHeight, (fp->body.y + fp->body.h * 0.5f) / (float)map->tileHeight);
+}
+
+kon_camera_t kon_fpCamera(const kon_fp_t *fp, const kon_tilemap_t *map)
+{
+	kon_camera_t camera = kon_cameraDefault();
+	kon_vec3_t eye = kon_fpEye(fp, map);
+
+	camera.position = eye;
+	camera.target = KON_VEC3(eye.x + sinf(fp->yaw) * cosf(fp->pitch), eye.y + sinf(fp->pitch), eye.z - cosf(fp->yaw) * cosf(fp->pitch));
+	camera.fov = fp->fov;
+	camera.nearZ = 0.05f;
+	camera.farZ = 40.0f;
+	return camera;
+}
+
+#if defined(KON_DEVELOPER) && defined(KON_MODULE_DEBUG)
+
+static void kon_cmdWhere_(kon_debug_t *debug, void *user, int argc, char **argv)
+{
+	kon_fp_t *fp = user;
+
+	(void)argc; (void)argv;
+	kon_debugLog(debug, "x %.1f  y %.1f  yaw %.2f  pitch %.2f", (double)fp->body.x, (double)fp->body.y, (double)fp->yaw, (double)fp->pitch);
+}
+
+void kon_fpDebug(kon_fp_t *fp, kon_debug_t *debug)
+{
+	kon_debugVar(debug, "sens", KON_VAR_FLOAT, &fp->sensitivity);
+	kon_debugVar(debug, "speed", KON_VAR_FLOAT, &fp->speed);
+	kon_debugVar(debug, "eye", KON_VAR_FLOAT, &fp->eyeHeight);
+	kon_debugCommand(debug, "where", "print where you stand in map pixels", kon_cmdWhere_, fp);
+}
+
+#else
+
+void kon_fpDebug(kon_fp_t *fp, kon_debug_t *debug)
+{
+	(void)fp; (void)debug;
+}
+
+#endif
+
+/*** drawing ***/
+
+void kon_drawLevel(kon_framebuffer_t *fb, const kon_camera_t *camera, const kon_level3d_t *level, const kon_light_t *light)
+{
+	const kon_tilemap_t *map = level->map;
+	kon_mat4_t vp = kon_cameraViewProjection(camera, fb->width, fb->height);
+	float fx = camera->target.x - camera->position.x, fz = camera->target.z - camera->position.z;
+	float flat = sqrtf(fx * fx + fz * fz), reach = camera->farZ + 1.0f;
+	float w = (float)map->columns, d = (float)map->rows, h = level->wallHeight;
+	int row, column;
+
+	/* looking straight up or down there is no direction to cull against */
+	if (flat > 0.001f) {
+		fx /= flat;
+		fz /= flat;
+	}
+
+	for (row = 0; row < map->rows; row++) {
+		for (column = 0; column < map->columns; column++) {
+			float x = (float)column, z = (float)row;
+			float dx = x + 0.5f - camera->position.x, dz = z + 0.5f - camera->position.z;
+
+			if (kon_open_(level, column, row)) continue;
+			if (dx * dx + dz * dz > reach * reach) continue;
+			if (flat > 0.001f && dx * fx + dz * fz < -2.0f) continue;
+
+			if (kon_open_(level, column, row - 1)) kon_wall_(fb, vp, level, light, KON_VEC3(x + 1, 0, z), KON_VEC3(x, 0, z), KON_VEC3(0, 0, -1));
+			if (kon_open_(level, column, row + 1)) kon_wall_(fb, vp, level, light, KON_VEC3(x, 0, z + 1), KON_VEC3(x + 1, 0, z + 1), KON_VEC3(0, 0, 1));
+			if (kon_open_(level, column - 1, row)) kon_wall_(fb, vp, level, light, KON_VEC3(x, 0, z), KON_VEC3(x, 0, z + 1), KON_VEC3(-1, 0, 0));
+			if (kon_open_(level, column + 1, row)) kon_wall_(fb, vp, level, light, KON_VEC3(x + 1, 0, z + 1), KON_VEC3(x + 1, 0, z), KON_VEC3(1, 0, 0));
+		}
+	}
+
+	if (level->floor) kon_quad_(fb, vp, level->floor, light, KON_VEC3(0, 0, 0), KON_VEC3(0, 0, d), KON_VEC3(w, 0, d), KON_VEC3(w, 0, 0),
+		KON_VEC3(0, 1, 0), KON_VEC2(0, 0), KON_VEC2(w, d));
+	if (level->ceiling) kon_quad_(fb, vp, level->ceiling, light, KON_VEC3(0, h, 0), KON_VEC3(w, h, 0), KON_VEC3(w, h, d), KON_VEC3(0, h, d),
+		KON_VEC3(0, -1, 0), KON_VEC2(0, 0), KON_VEC2(w, d));
+}
+
+float kon_distanceFade(float distance, float falloff)
+{
+	return 1.0f / (1.0f + distance * falloff);
+}
diff --git a/kon/kon3d.h b/kon/kon3d.h
new file mode 100644
index 0000000..e4ffc6b
--- /dev/null
+++ b/kon/kon3d.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * kon3d.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 KON3D_H
+#define KON3D_H
+
+#include "konprogram.h"
+#include "kontile.h"
+
+/*** definition ***/
+
+/* a first person body on a tilemap. the world is one unit per tile, y is up, yaw 0 looks up the map (towards row 0) */
+typedef struct kon_fp {
+	kon_box2_t body;   /* map pixels, this is what bumps into walls */
+	float eyeHeight;   /* world units, 0.6 */
+	float yaw, pitch;
+	float sensitivity; /* radians per mouse pixel, 0.0015 */
+	float speed;       /* tiles per second, 2.5 */
+	float turnSpeed;   /* radians per second for the arrow keys, 2 */
+	float fov;         /* vertical, radians, 60 degrees */
+	int forward, strafe, turn; /* -1, 0 or 1, set by kon_fpEvent */
+} kon_fp_t;
+
+/* what to draw for a map. solid is indexed by tile id like in kon_tilemapMove, solid tiles become walls.
+   ceiling can be NULL, that leaves the sky colour */
+typedef struct kon_level3d {
+	const kon_tilemap_t *map;
+	const uint8_t *solid;
+	int solidCount;
+	float wallHeight;
+	const kon_material_t *wall, *floor, *ceiling;
+} kon_level3d_t;
+
+/*** body ***/
+
+/* stands in the middle of the tile, looking up the map */
+void kon_fpInit(kon_fp_t *fp, const kon_tilemap_t *map, int column, int row);
+
+/* returns 1 when the event was used. wasd and the arrows walk, the mouse looks once it is captured,
+   a click grabs the mouse and tab lets go */
+int kon_fpEvent(kon_fp_t *fp, kon_program_t *program, const kon_event_t *event);
+
+/* walks and turns, slides along solid tiles. lets the mouse go while the debug console is open */
+void kon_fpUpdate(kon_fp_t *fp, kon_program_t *program, const kon_tilemap_t *map, const uint8_t *solid, int solidCount, double dt);
+
+/* where the eyes are in world units */
+kon_vec3_t kon_fpEye(const kon_fp_t *fp, const kon_tilemap_t *map);
+kon_camera_t kon_fpCamera(const kon_fp_t *fp, const kon_tilemap_t *map);
+
+/* adds the variables sens, speed and eye and the command where */
+void kon_fpDebug(kon_fp_t *fp, kon_debug_t *debug);
+
+/*** drawing ***/
+
+/* walls, floor and ceiling. walls behind the camera and far away ones are skipped, floor and ceiling go last
+   so the depth test throws out what the walls already cover */
+void kon_drawLevel(kon_framebuffer_t *fb, const kon_camera_t *camera, const kon_level3d_t *level, const kon_light_t *light);
+
+/* 1 up close and less the further away, for dimming sprites. falloff 0.18 is gentle */
+float kon_distanceFade(float distance, float falloff);
+
+#endif