started platform building

5 files changed, 130 insertions, 24 deletions

diff --git a/gui.hpp b/gui.hpp
index 39adb54..f40c361 100644
--- a/gui.hpp
+++ b/gui.hpp
@@ -33,11 +33,26 @@ enum {
 };
 typedef u16 Key;
 
+#define MOUSE_LEFT 0
+#define MOUSE_MIDDLE 1
+#define MOUSE_RIGHT 2
+
+typedef struct {
+	u8 button;
+	i32 x, y;
+} MousePress;
+typedef MousePress MouseRelease;
+
 typedef struct {
 	bool closed; // was the window closed?
 	u8 keys_pressed[NKEYS];  // [i] = how many times was key #i pressed  this frame?
 	u8 keys_released[NKEYS]; // [i] = how many times was key #i released this frame?
 	bool keys_down[NKEYS]; // [i] = is key #i down?
+	u16 nmouse_presses;
+#define MAX_MOUSE_PRESSES_PER_FRAME 256
+	MousePress mouse_presses[MAX_MOUSE_PRESSES_PER_FRAME];
+
+	i32 mouse_x, mouse_y; // (+y = down)
 	bool shift, ctrl;
 } Input;
 
diff --git a/main.cpp b/main.cpp
index ad5daaf..7fe4994 100644
--- a/main.cpp
+++ b/main.cpp
@@ -388,6 +388,11 @@ int main(void) {
 			SDL_GetWindowSize(window, &w, &h);
 			frame.width = w;
 			frame.height = h;
+
+			int x = 0, y = 0;
+			SDL_GetMouseState(&x, &y);
+			input->mouse_x = x;
+			input->mouse_y = y;
 		}
 		
 		{
diff --git a/math.cpp b/math.cpp
index 25c5917..fcaa162 100644
--- a/math.cpp
+++ b/math.cpp
@@ -267,6 +267,10 @@ static v3 v3_normalize(v3 v) {
 	return v3_scale(v, mul);
 }
 
+static v2 v3_xy(v3 v) {
+	return V2(v.x, v.y);
+}
+
 // a point on a unit sphere 
 static v3 v3_on_sphere(float yaw, float pitch) {
 	return V3(cosf(yaw) * cosf(pitch), sinf(pitch), sinf(yaw) * cosf(pitch));
@@ -495,6 +499,41 @@ static m4 m4_mul(m4 a, m4 b) {
 	return prod;
 }
 
+static m4 m4_inv(m4 mat) {
+	m4 ret;
+	float *inv = ret.e;
+	float *m = mat.e;
+
+	inv[0] = m[5] * m[10] * m[15] - m[5] * m[11] * m[14] - m[9] * m[6] * m[15] + m[9] * m[7] * m[14] + m[13] * m[6] * m[11] - m[13] * m[7] * m[10];
+	inv[4] = -m[4] * m[10] * m[15] + m[4] * m[11] * m[14] + m[8] * m[6] * m[15] - m[8] * m[7] * m[14] - m[12] * m[6] * m[11] + m[12] * m[7] * m[10];
+	inv[8] = m[4] * m[9] * m[15] - m[4] * m[11] * m[13] - m[8] * m[5] * m[15] + m[8] * m[7] * m[13] + m[12] * m[5] * m[11] - m[12] * m[7] * m[9];
+	inv[12] = -m[4] * m[9] * m[14] + m[4] * m[10] * m[13] + m[8] * m[5] * m[14] - m[8] * m[6] * m[13] - m[12] * m[5] * m[10] + m[12] * m[6] * m[9];
+	inv[1] = -m[1] * m[10] * m[15] + m[1] * m[11] * m[14] + m[9] * m[2] * m[15] - m[9] * m[3] * m[14] - m[13] * m[2] * m[11] + m[13] * m[3] * m[10];
+	inv[5] = m[0] * m[10] * m[15] - m[0] * m[11] * m[14] - m[8] * m[2] * m[15] + m[8] * m[3] * m[14] + m[12] * m[2] * m[11] - m[12] * m[3] * m[10];
+	inv[9] = -m[0] * m[9] * m[15] + m[0] * m[11] * m[13] + m[8] * m[1] * m[15] - m[8] * m[3] * m[13] - m[12] * m[1] * m[11] + m[12] * m[3] * m[9];
+	inv[13] = m[0] * m[9] * m[14] - m[0] * m[10] * m[13] - m[8] * m[1] * m[14] + m[8] * m[2] * m[13] + m[12] * m[1] * m[10] - m[12] * m[2] * m[9];
+	inv[2] = m[1] * m[6] * m[15] - m[1] * m[7] * m[14] - m[5] * m[2] * m[15] + m[5] * m[3] * m[14] + m[13] * m[2] * m[7] - m[13] * m[3] * m[6];
+	inv[6] = -m[0] * m[6] * m[15] + m[0] * m[7] * m[14] + m[4] * m[2] * m[15] - m[4] * m[3] * m[14] - m[12] * m[2] * m[7] + m[12] * m[3] * m[6];
+	inv[10] = m[0] * m[5] * m[15] - m[0] * m[7] * m[13] - m[4] * m[1] * m[15] + m[4] * m[3] * m[13] + m[12] * m[1] * m[7] - m[12] * m[3] * m[5];
+	inv[14] = -m[0] * m[5] * m[14] + m[0] * m[6] * m[13] + m[4] * m[1] * m[14] - m[4] * m[2] * m[13] - m[12] * m[1] * m[6] + m[12] * m[2] * m[5];
+	inv[3] = -m[1] * m[6] * m[11] + m[1] * m[7] * m[10] + m[5] * m[2] * m[11] - m[5] * m[3] * m[10] - m[9] * m[2] * m[7] + m[9] * m[3] * m[6];
+	inv[7] = m[0] * m[6] * m[11] - m[0] * m[7] * m[10] - m[4] * m[2] * m[11] + m[4] * m[3] * m[10] + m[8] * m[2] * m[7] - m[8] * m[3] * m[6];
+	inv[11] = -m[0] * m[5] * m[11] + m[0] * m[7] * m[9] + m[4] * m[1] * m[11] - m[4] * m[3] * m[9] - m[8] * m[1] * m[7] + m[8] * m[3] * m[5];
+	inv[15] = m[0] * m[5] * m[10] - m[0] * m[6] * m[9] - m[4] * m[1] * m[10] + m[4] * m[2] * m[9] + m[8] * m[1] * m[6] - m[8] * m[2] * m[5];
+
+	float det = m[0] * inv[0] + m[1] * inv[4] + m[2] * inv[8] + m[3] * inv[12];
+
+	if (det == 0) {
+		memset(inv, 0, sizeof *inv);
+	} else {
+		det = 1 / det;
+
+		for (int i = 0; i < 16; i++)
+			inv[i] *= det;
+	}
+
+	return ret;
+}
 typedef struct {
 	int x, y;
 } v2i;
diff --git a/sim.cpp b/sim.cpp
index 49cdeef..70a2830 100644
--- a/sim.cpp
+++ b/sim.cpp
@@ -187,6 +187,8 @@ static void platforms_render(State *state, Platform *platforms, u32 nplatforms)
 		v2 endpoint1 = v2_add(center, platform_r);
 		v2 endpoint2 = v2_sub(center, platform_r);
 
+		gl_rgbacolor(platform->color);
+
 	#if 1
 		gl->VertexAttrib2f(shader->vertex_p1, endpoint1.x, endpoint1.y);
 		gl->VertexAttrib2f(shader->vertex_p2, endpoint2.x, endpoint2.y);
@@ -346,8 +348,8 @@ void sim_frame(Frame *frame) {
 	maybe_unused u8 *keys_pressed = input->keys_pressed;
 	maybe_unused bool *keys_down = input->keys_down;
 
-	state->win_width  = width;
-	state->win_height = height;
+	state->win_width  = (float)width;
+	state->win_height = (float)height;
 	state->dt = (float)frame->dt;
 	
 
@@ -459,25 +461,23 @@ void sim_frame(Frame *frame) {
 			p->center = V2(-1.0f, 5.0f);
 			p->angle  = 0;
 			p->size   = 1.0f;
-			//p->rotate_speed = -1.0f;
-			platform_make_body(state, p);
-			++p;
-			p->moves = true;
-			p->move_p1 = V2(2.0f, 0.5f);
-			p->move_p2 = V2(-2.0f, 1.5f);
-			p->move_speed = 1.0f;
-			p->angle  = 0.05f;
-			p->size   = 6.0f;
+			p->color = 0xFF00FFFF;
 			platform_make_body(state, p);
 			state->nplatforms = (u32)(p - state->platforms + 1);
-		}
 
+			Platform *b = &state->platform_building;
+			b->size = 3.0f;
+			b->color = 0xFF00FF7F;
+		}
+		
+		state->building = true;
+			
 		state->initialized = true;
 	#if DEBUG
 		state->magic_number = MAGIC_NUMBER;
 	#endif
 	}
-	if (input->keys_pressed[KEY_ESCAPE]) {
+	if (keys_pressed[KEY_ESCAPE]) {
 		frame->close = true;
 		return;
 	}
@@ -486,25 +486,61 @@ void sim_frame(Frame *frame) {
 	shaders_reload_if_necessary(state);
 #endif
 
-	maybe_unused b2World *world = state->world;
+	{
+		float half_height = 10.0f;
+		float half_width = half_height * state->win_width / state->win_height;
+		float ball_x = ball->pos.x, ball_y = ball->pos.y;
+		// center view around ball
+		state->transform = m4_ortho(ball_x - half_width, ball_x + half_width, ball_y - half_height, ball_y + half_height, -1, +1);
+		state->inv_transform = m4_inv(state->transform);
+	}
+
+	{ // calculate mouse position in Box2D coordinates
+		v3 mouse_gl_coords = V3(
+			(float)input->mouse_x / state->win_width * 2 - 1,
+			(1 - (float)input->mouse_y / state->win_height) * 2 - 1,
+			0
+		);
+
+		state->mouse_pos = v3_xy(m4_mul_v3(state->inv_transform, mouse_gl_coords));
+	}
+
 	Font *font = &state->font;
 
-	// simulate physics
-	{
+	if (state->simulating) {
+		// simulate physics
 		float dt = state->dt;
 		if (dt > 100) dt = 100; // prevent floating-point problems for very large dt's
 		simulate_time(state, dt);
 	}
 
-	{
-		float half_height = 10.0f;
-		float half_width = half_height * (float)state->win_width / (float)state->win_height;
-		float ball_x = ball->pos.x, ball_y = ball->pos.y;
-		// center view around ball
-		state->transform = m4_ortho(ball_x - half_width, ball_x + half_width, ball_y - half_height, ball_y + half_height, -1, +1);
+	if (state->building) {
+		Platform *platform_building = &state->platform_building;
+		platform_building->center = state->mouse_pos;
+		float dt = state->dt;
+		float rotate_amount = 2.0f * dt;
+		float size_change_amount = 4.0f * dt;
+		// rotate platform using left/right
+		if (keys_down[KEY_LEFT])
+			platform_building->angle += rotate_amount;
+		if (keys_down[KEY_RIGHT])
+			platform_building->angle -= rotate_amount;
+		
+		// change size of platform using up/down
+		if (keys_down[KEY_UP])
+			platform_building->size += size_change_amount;
+		if (keys_down[KEY_DOWN])
+			platform_building->size -= size_change_amount;
+
+		platform_building->size = clampf(platform_building->size, 0.3f, 10.0f);
+		platform_building->angle = fmodf(platform_building->angle, TAUf);
 	}
 
+
 	platforms_render(state, state->platforms, state->nplatforms);
+	if (state->building) {
+		platforms_render(state, &state->platform_building, 1);
+	}
 	ball_render(state);
 
 	{
diff --git a/sim.hpp b/sim.hpp
index 0f4dbd7..dcc32fb 100644
--- a/sim.hpp
+++ b/sim.hpp
@@ -138,7 +138,10 @@ typedef struct {
 	v2 move_p1;
 	v2 move_p2;
 
+
 	float rotate_speed;
+
+	u32 color;
 } Platform;
 
 typedef struct {
@@ -150,7 +153,9 @@ typedef struct {
 typedef struct {
 	bool initialized;
 
-	i32 win_width, win_height; // width,height of window
+	float win_width, win_height; // width,height of window in pixels
+
+	v2 mouse_pos; // mouse position in Box2D (not GL) coordinates
 
 	float dt; // time in seconds since last frame
 
@@ -159,12 +164,16 @@ typedef struct {
 	// will be some left over, if the frame time is not a multiple of the fixed time step)
 	float time_residue; 
 	m4 transform; // the transform for converting our coordinates to GL coordinates
+	m4 inv_transform; // inverse of transform (for converting GL coordinates to our coordinates)
 
 	GL gl; // gl functions
 	ShaderPlatform shader_platform;
 	ShaderBall shader_ball;
 
-	b2World *world;
+	bool building; // is the user building a setup?
+	bool simulating; // are we simulating the world's physics?
+
+	b2World *world; // Box2D world
 
 	Ball ball;
 	float bottom_y; // y-position of "floor" (if y goes below here, it's over)
@@ -172,6 +181,8 @@ typedef struct {
 
 	Font font;
 
+	Platform platform_building; // the platform the user is currently placing
+
 	float platform_thickness;
 	u32 nplatforms;
 	Platform platforms[1000];