Add a simple camera struct and camera controls

5 files changed, 125 insertions, 16 deletions

diff --git a/Makefile b/Makefile
index 9d66590..498123c 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,7 @@ CFLAGS += $(shell $(PKG_CONFIG) --cflags $(LIBS)) -std=c11 -MMD -MP
 LDFLAGS += -Wl,--as-needed
 LDLIBS += $(shell $(PKG_CONFIG) --libs $(LIBS)) -lm
 
-OBJ := faqe.o ensize.o eprintf.o fmd.o gl.o glprog.o ieee754.o model.o mtl.o tex.o
+OBJ := faqe.o camera.o ensize.o eprintf.o fmd.o gl.o glprog.o ieee754.o model.o mtl.o tex.o
 
 all: $(PROG)
 
diff --git a/camera.c b/camera.c
new file mode 100644
index 0000000..6335d0e
--- /dev/null
+++ b/camera.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2018 Tomasz Kramkowski <tk@the-tk.com>
+ * SPDX-License-Identifier: MIT
+ */
+#include <assert.h>
+#include <math.h>
+#include <stdlib.h>
+
+#include "camera.h"
+#include "math.h"
+
+#define PITCH_LIMIT (PI * 0.99)
+
+void camera_clamp(struct camera *cam)
+{
+	assert(cam != NULL);
+
+	cam->yaw = fmod(cam->yaw, 2 * PI);
+	if (cam->pitch > PITCH_LIMIT / 2)
+		cam->pitch = PITCH_LIMIT / 2;
+	else if (cam->pitch < -PITCH_LIMIT / 2)
+		cam->pitch = -PITCH_LIMIT / 2;
+}
+void camera_dir(vec3 out, struct camera *cam)
+{
+	assert(out != NULL);
+	assert(cam != NULL);
+
+	out[0] = cosf(cam->pitch) * cosf(cam->yaw);
+	out[1] = sinf(cam->pitch);
+	out[2] = cosf(cam->pitch) * sinf(cam->yaw);
+}
+void camera_lookat(mat4x4 out, struct camera *cam)
+{
+	vec3 at, dir;
+
+	assert(out != NULL);
+	assert(cam != NULL);
+
+	camera_dir(dir, cam);
+	vec3_add(at, cam->pos, dir);
+	mat4x4_look_at(out, cam->pos, at, (vec3){ 0, 1, 0 });
+}
diff --git a/camera.h b/camera.h
new file mode 100644
index 0000000..6d8bb94
--- /dev/null
+++ b/camera.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2018 Tomasz Kramkowski <tk@the-tk.com>
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef CAMERA_H
+#define CAMERA_H
+
+#include "linmath.h"
+
+#define CAM_UP ((vec3){ 0.0, 1.0, 0.0 })
+
+struct camera {
+	vec3 pos;
+	float pitch;
+	float yaw;
+};
+
+void camera_clamp(struct camera *cam);
+void camera_dir(vec3 out, struct camera *cam);
+void camera_lookat(mat4x4 out, struct camera *cam);
+
+#endif // CAMERA_H
diff --git a/faqe.c b/faqe.c
index 1983464..3b81e24 100644
--- a/faqe.c
+++ b/faqe.c
@@ -6,19 +6,20 @@
 #include <stdbool.h>
 
 #include "assets.h"
+#include "camera.h"
 #include "eprintf.h"
 #include "gl.h"
 #include "glprog.h"
 #include "linmath.h"
-#include "nelem.h"
+#include "math.h"
 #include "model.h"
+#include "nelem.h"
 
 enum {
 	WIDTH = 800,
 	HEIGHT = 600,
 };
 
-#define PI 3.14159265358979323846
 #define FOV (PI * 0.5)
 
 void viewport(GLuint proj, int width, int height)
@@ -38,11 +39,14 @@ int main(int argc, char **argv)
 	struct {
 		GLint model, view, proj, tex;
 	} uni;
-	mat4x4 view;
 	FILE *cube_file;
 	struct fmd cube_fmd;
 	struct model cube_model;
-	vec3 pos = { 0, 0, 3 };
+	struct camera cam = { .pos = { 0.0, 0.0, 3.0 }, .yaw = -PI/2 };
+	struct {
+		bool w, a, s, d, spc, lct;
+	} key = { 0 };
+	float tlast;
 
 	setprogname(argc >= 1 && argv[0] != NULL ? argv[0] : "faqe");
 
@@ -61,6 +65,8 @@ int main(int argc, char **argv)
 	if (win == NULL)
 		eprintf("Failed to create window: %s", SDL_GetError());
 
+	SDL_SetRelativeMouseMode(SDL_TRUE);
+
 	glc = SDL_GL_CreateContext(win);
 	if (glc == NULL)
 		eprintf("Failed to create OpenGL context: %s", SDL_GetError());
@@ -97,20 +103,33 @@ int main(int argc, char **argv)
 	gl_enable(GL_FRAMEBUFFER_SRGB);
 	gl_enable(GL_CULL_FACE);
 
+	tlast = SDL_GetTicks() * 0.0001;
+
 	while (running) {
-		mat4x4 model;
+		mat4x4 model, view;
+		vec3 dir, right, motion = { 0 }, strafe = { 0 };
 		SDL_Event ev;
-		float secs;
-
-		secs = SDL_GetTicks() * 0.0001;
-
-		mat4x4_look_at(view, pos, (vec3){ 0, 0, 0 }, (vec3){ 0, 1, 0 });
-		gl_uni_setm4fv(uni.view, 1, GL_FALSE, view[0]);
+		float tdiff, tnow;
 
 		while (SDL_PollEvent(&ev)) {
+			bool down;
 			switch (ev.type) {
+			case SDL_MOUSEMOTION:
+				cam.yaw += ev.motion.xrel * 0.005;
+				cam.pitch += ev.motion.yrel * -0.005;
+				camera_clamp(&cam);
+				break;
 			case SDL_KEYDOWN:
 			case SDL_KEYUP:
+				down = ev.key.state == SDL_PRESSED;
+				switch (ev.key.keysym.sym) {
+				case SDLK_w: key.w = down; break;
+				case SDLK_a: key.a = down; break;
+				case SDLK_s: key.s = down; break;
+				case SDLK_d: key.d = down; break;
+				case SDLK_SPACE: key.spc = down; break;
+				case SDLK_LCTRL: key.lct = down; break;
+				}
 				if (ev.key.state != SDL_RELEASED
 				    || ev.key.keysym.sym != SDLK_ESCAPE)
 					break;
@@ -129,13 +148,28 @@ int main(int argc, char **argv)
 			}
 		}
 
+		tnow = SDL_GetTicks() * 0.001;
+		tdiff = tnow - tlast;
+		tlast = tnow;
+
+		camera_dir(dir, &cam);
+		vec3_mul_cross(right, dir, CAM_UP);
+		vec3_norm(right, right);
+
+		if (key.w != key.s) vec3_scale(motion, dir, tdiff * (key.w ? 1 : -1));
+		if (key.a != key.d) vec3_scale(strafe, right, tdiff * (key.d ? 1 : -1));
+		if (key.spc != key.lct) cam.pos[1] += tdiff * (key.spc ? 1 : -1);
+		vec3_add(cam.pos, cam.pos, strafe);
+		vec3_add(cam.pos, cam.pos, motion);
+
+		camera_lookat(view, &cam);
+
 		gl_clearcolor(0.2, 0.3, 0.3, 1.0);
 		gl_clear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-		gl_prog_use(prog);
 		mat4x4_identity(model);
-		mat4x4_rotate_X(model, model, secs * 3);
-		mat4x4_rotate_Y(model, model, secs * 2);
-		mat4x4_rotate_Z(model, model, secs * 4);
+
+		gl_prog_use(prog);
+		gl_uni_setm4fv(uni.view, 1, GL_FALSE, view[0]);
 		gl_uni_setm4fv(uni.model, 1, GL_FALSE, model[0]);
 		model_render(&cube_model);
 		gl_va_bind(0);
diff --git a/math.h b/math.h
new file mode 100644
index 0000000..e5b9724
--- /dev/null
+++ b/math.h
@@ -0,0 +1,10 @@
+/*
+ * Copyright (C) 2018 Tomasz Kramkowski <tk@the-tk.com>
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef MATH_H
+#define MATH_H
+
+#define PI 3.14159265358979323846
+
+#endif // MATH_H