commit 038e30e7e25f9d000f95ff3de3e7d2db8134c2eb
parent 9fd697f486d2948239832e5056377946c2e510c3
Author: amin <dev@aminmesbah.com>
Date: Sun, 23 Jun 2019 06:30:18 +0000
Merge branch 'features/replace-math-functions' into features/wasm-without-emscripten
FossilOrigin-Name: 7662e7f21e847fdbbb6c37d3ae29045102f88e84fbd806b4ec6babb20ba9dbfc
Diffstat:
4 files changed, 123 insertions(+), 52 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,6 +1,6 @@
CC = clang
CFLAGS = -std=c99 -Ilib -Wall -Wextra -Wshadow -Wswitch-enum -Wno-unused-parameter -Wno-missing-braces
-LDFLAGS = -ldl -lglfw -lGL -lm
+LDFLAGS = -ldl -lglfw -lGL
SRC_FILES = platform_linux.c
SRC = $(addprefix src/, $(SRC_FILES))
diff --git a/src/game.c b/src/game.c
@@ -90,8 +90,7 @@ void game_update_and_render(struct GameState *game_state, float dt, u32 screen_w
m4 view = glmth_m4_init_id();
m4 projection = glmth_m4_init_id();
view = glmth_translate(view, glmth_v3_init(0.0f, 0.0f, -3.0f));
- //projection = glmth_projection_perspective_fov(glmth_rad(45.0f), (float)screen_width / (float)screen_height, 0.1f, 100.0f);
- projection = glmth_projection_ortho(0.0f, screen_width, 0.0f, screen_height, -10.0f, 10.0f);
+ projection = glmth_projection_perspective_fov(glmth_rad(45.0f), (float)screen_width / (float)screen_height, 0.1f, 100.0f);
// render cube
{
@@ -110,11 +109,13 @@ void game_update_and_render(struct GameState *game_state, float dt, u32 screen_w
m4 model = glmth_m4_init_id();
f32 angle = 20.0f;
- model = glmth_rotate(model, dt * glmth_rad(angle), glmth_v3_init(1.0f, 0.0f, 0.0f));
- model = glmth_rotate(model, dt * glmth_rad(angle), glmth_v3_init(0.0f, 1.0f, 0.0f));
- model = glmth_rotate(model, dt * glmth_rad(angle), glmth_v3_init(0.0f, 0.0f, 1.0f));
+ // TODO: fmodf this so we don't get huge numbers eventually
+ f32 rot_rad = dt * glmth_rad(angle);
+ model = glmth_rotate(model, rot_rad, glmth_v3_init(1.0f, 0.0f, 0.0f));
+ model = glmth_rotate(model, rot_rad, glmth_v3_init(0.0f, 1.0f, 0.0f));
+ model = glmth_rotate(model, rot_rad, glmth_v3_init(0.0f, 0.0f, 1.0f));
- f32 alpha = 0.2f * (1.5f + sinf(0.5f * dt));
+ f32 alpha = 0.2f * (1.5f + glmth_sinf(0.5f * dt));
shader_setm4(&game_state->cube_shader, "model", &model);
shader_setf(&game_state->cube_shader, "alpha", alpha);
diff --git a/src/game.h b/src/game.h
@@ -9,31 +9,6 @@
// TODO: fix this
#define assert(x) (void)0
-inline float sinf(float x)
-{
- return x;
-}
-
-inline float cosf(float x)
-{
- return x;
-}
-
-inline float powf(float x, float p)
-{
- return x * x;
-}
-
-inline float sqrtf(float a)
-{
- return a * 0.5f;
-}
-
-inline float tanf(float a)
-{
- return 0.4142135623730950488f;
-}
-
typedef _Bool bool;
#define true 1
#define false 0
diff --git a/src/glmth.h b/src/glmth.h
@@ -15,6 +15,115 @@ typedef signed long long i64;
typedef float f32;
typedef double f64;
+#define GLMTH_PI 3.14159265358979323846f
+#define GLMTH_M_2_PI 6.28318530717958647693f
+#define GLMTH_D_4_PI 1.27323954473516268615f
+#define GLMTH_D_PI_2 1.57079632679489661923f
+#define GLMTH_D_4_SQ_PI 0.40528473456935108578f
+
+static inline f32 glmth_floorf(f32 x)
+{
+ f32 result = (f32)((i32)x - (x < 0.0f));
+ return result;
+}
+
+// These Sine and Cosine approximations use a parabola adjusted to minimize
+// error. This lovely approximation was derived by "Nick" on the devmaster.net
+// forums:
+//
+// https://web.archive.org/web/20080228213915/http://www.devmaster.net/forums/showthread.php?t=5784
+static inline f32 glmth_sinf(f32 x)
+{
+
+ // wrap to range [0, 2PI]
+ f32 full_circles = glmth_floorf(x / GLMTH_M_2_PI);
+ f32 full_circle_radians = full_circles * GLMTH_M_2_PI;
+ x = x - full_circle_radians;
+
+ // TODO: remove branches
+ // wrap to range [-PI, PI]
+ if(x < -GLMTH_PI)
+ {
+ x += GLMTH_M_2_PI;
+ }
+ else if(x > GLMTH_PI)
+ {
+ x -= GLMTH_M_2_PI;
+ }
+
+ // fit parabola to sine
+ f32 f = 0.0f;
+ f32 g = 0.0f;
+ if(x < 0.0f)
+ {
+ f = (GLMTH_D_4_PI * x) + (GLMTH_D_4_SQ_PI * x * x);
+ g = f * -f;
+
+ }
+ else
+ {
+ f = (GLMTH_D_4_PI * x) - (GLMTH_D_4_SQ_PI * x * x);
+ g = f * f;
+ }
+
+ f32 h = g - f;
+ f32 i = h * 0.225f;
+ f = i + f;
+
+ return f;
+}
+
+static inline f32 glmth_cosf(f32 x)
+{
+ // wrap to range [0, 2PI]
+ f32 full_circles = glmth_floorf(x / GLMTH_M_2_PI);
+ f32 full_circle_radians = full_circles * GLMTH_M_2_PI;
+ x = x - full_circle_radians;
+
+ // TODO: remove branches
+ // wrap to range [-PI, PI]
+ if(x < -GLMTH_PI)
+ {
+ x += GLMTH_M_2_PI;
+ }
+ else if(x > GLMTH_PI)
+ {
+ x -= GLMTH_M_2_PI;
+ }
+
+ x += GLMTH_D_PI_2;
+ if(x > GLMTH_PI)
+ {
+ x -= GLMTH_M_2_PI;
+ }
+
+ // fit parabola to cosine
+ f32 f = 0.0f;
+ f32 g = 0.0f;
+ if(x < 0.0f)
+ {
+ f = (GLMTH_D_4_PI * x) + (GLMTH_D_4_SQ_PI * x * x);
+ g = f * -f;
+
+ }
+ else
+ {
+ f = (GLMTH_D_4_PI * x) - (GLMTH_D_4_SQ_PI * x * x);
+ g = f * f;
+ }
+
+ f32 h = g - f;
+ f32 i = h * 0.225f;
+ f = i + f;
+ return f;
+}
+
+static inline f32 glmth_tanf(f32 x)
+{
+ // TODO: make a proper approximation
+ return glmth_sinf(x)/glmth_cosf(x);
+}
+
typedef union
{
struct
@@ -137,18 +246,6 @@ static inline v3 glmth_v3_init(f32 x, f32 y, f32 z)
return v;
}
-static inline f32 glmth_v3_length(v3 v)
-{
- return sqrtf((v.x * v.x) + (v.y * v.y) + (v.z * v.z));
-}
-
-static inline v3 glmth_v3_normalize(v3 v)
-{
- f32 l = glmth_v3_length(v);
- v3 r = glmth_v3_init(v.x / l, v.y / l, v.z / l);
- return r;
-}
-
static inline f32 glmth_rad(f32 deg)
{
return deg * (M_PI / 180.0f);
@@ -156,24 +253,22 @@ static inline f32 glmth_rad(f32 deg)
static inline m4 glmth_rotate(m4 m, f32 rad, v3 axis)
{
- //axis = glmth_v3_normalize(axis);
-
- f32 c = cosf(rad);
- f32 s = sinf(rad);
+ f32 c = glmth_cosf(rad);
+ f32 s = glmth_sinf(rad);
m4 r = glmth_m4_init_id();
- r.E[0][0] = c + (powf(axis.x, 2.0f) * (1 - c));
+ r.E[0][0] = c + ((axis.x * axis.x) * (1 - c));
r.E[0][1] = (axis.x * axis.y * (1 - c)) - (axis.z * s);
r.E[0][2] = (axis.x * axis.z * (1 - c)) + (axis.y * s);
r.E[1][0] = (axis.y * axis.x * (1 - c)) + (axis.z * s);
- r.E[1][1] = c + (powf(axis.y, 2.0f) * (1 - c));
+ r.E[1][1] = c + ((axis.y * axis.y) * (1 - c));
r.E[1][2] = (axis.y * axis.z * (1 - c)) - (axis.x * s);
r.E[2][0] = (axis.z * axis.x * (1 - c)) - (axis.y * s);
r.E[2][1] = (axis.z * axis.y * (1 - c)) + (axis.x * s);
- r.E[2][2] = c + (powf(axis.z, 2.0f) * (1 - c));
+ r.E[2][2] = c + ((axis.z * axis.z) * (1 - c));
return glmth_m4m4_m(m, r);
}
@@ -252,7 +347,7 @@ static inline m4 glmth_projection_perspective(f32 left, f32 right, f32 bottom, f
static inline m4 glmth_projection_perspective_fov(f32 fovy, f32 aspect, f32 near, f32 far)
{
- f32 half_height = tanf(fovy / 2.0f) * near;
+ f32 half_height = glmth_tanf(fovy / 2.0f) * near;
f32 half_width = half_height * aspect;
f32 left = -half_width;
f32 right = half_width;
