commit 23ed0bb66855cfc578f9f9bd4c3c7572935e1df7
parent 6a8cc2d2baa68ea94fffce96f4d857bdbb784393
Author: amin <dev@aminmesbah.com>
Date: Fri, 17 Mar 2017 18:57:21 +0000
Implement basic fixed timestep.
There still seems to be some jittering, and I'll need to carefully
figure out what's causing it. Also, when the window is expanded to a
large size (like 1920 x 1080), the updates begin to take too long and
the game becomes unresponsive.
FossilOrigin-Name: a8cae097c36b6495ff019614825f624c54b222558102287afa085ad25dea7905
Diffstat:
| M | sdl_tunnel_runner.cpp | | | 189 | +++++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------- |
1 file changed, 128 insertions(+), 61 deletions(-)
diff --git a/sdl_tunnel_runner.cpp b/sdl_tunnel_runner.cpp
@@ -3,6 +3,8 @@
#include <stdio.h>
#include <stdint.h>
#include <sys/mman.h>
+#include <time.h>
+#include <unistd.h>
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
@@ -32,6 +34,12 @@ typedef uint64_t uint64;
#define CONTROLLER_STICK_MAX 32770
#define CONTROLLER_STICK_MIN -32770
+#define SECOND 1000.0f
+#define FPS 60
+#define MS_PER_FRAME (SECOND / FPS)
+#define UPDATES_PER_SECOND 65
+#define MS_PER_UPDATE (SECOND / UPDATES_PER_SECOND)
+
struct SDLOffscreenBuffer
{
@@ -65,23 +73,41 @@ global_variable SDL_Haptic *rumble_handles[MAX_CONTROLLERS];
global_variable TransformData transform;
+uint64_t
+get_current_time_ms(void)
+{
+ struct timespec current;
+ // TODO(amin): Fallback to other time sources when CLOCK_MONOTONIC is unavailable.
+ clock_gettime(CLOCK_MONOTONIC, ¤t);
+ uint64_t milliseconds = ((current.tv_sec * 1000000000) + current.tv_nsec) / 1000000;
+ return milliseconds;
+}
+
+
internal void
-render_mosaic(SDLOffscreenBuffer buffer, int x_offset, int y_offset, char color_choice)
+render_texture(
+ SDLOffscreenBuffer buffer,
+ uint32 texture[TEX_HEIGHT][TEX_WIDTH],
+ int x_offset,
+ int y_offset,
+ char color_choice)
{
uint8 *row = (uint8 *)buffer.memory;
for (int y = 0; y < buffer.height; ++y)
{
uint32 *pixel = (uint32 *)row;
-
for (int x = 0; x < buffer.width; ++x)
{
- uint8 x_factor = (x + x_offset);
- uint8 y_factor = (y + y_offset);
- uint8 color_value (x_factor * x_factor * y_factor * y_factor);
- uint32 red = color_value << 16;
- uint32 green = color_value << 8;
- uint32 blue = color_value;
+ uint8 color = texture[
+ (unsigned int)(y + y_offset) % TEX_HEIGHT
+ ]
+ [
+ (unsigned int)(x + x_offset) % TEX_WIDTH
+ ];
+ uint32 red = color << 16;
+ uint32 green = color << 8;
+ uint32 blue = color;
switch(color_choice)
{
@@ -121,6 +147,78 @@ render_mosaic(SDLOffscreenBuffer buffer, int x_offset, int y_offset, char color_
}
+internal void
+render_tunnel(
+ SDLOffscreenBuffer buffer,
+ uint32 texture[TEX_HEIGHT][TEX_WIDTH],
+ int rotation_offset,
+ int translation_offset,
+ char color_choice)
+{
+ uint8 *row = (uint8 *)buffer.memory;
+
+ for (int y = 0; y < buffer.height; ++y)
+ {
+ uint32 *pixel = (uint32 *)row;
+ for (int x = 0; x < buffer.width; ++x)
+ {
+ uint8 color = texture[
+ (unsigned int)(
+ transform.distance_table[y + transform.look_shift_y][x + transform.look_shift_x]
+ + translation_offset
+ )
+ % TEX_HEIGHT
+ ]
+ [
+ (unsigned int)(
+ transform.angle_table[y + transform.look_shift_y][x + transform.look_shift_x]
+ + rotation_offset
+ )
+ % TEX_WIDTH
+ ];
+
+ uint32 red = color << 16;
+ uint32 green = color << 8;
+ uint32 blue = color;
+
+ // TODO(amin): Make a color choice enum
+ switch(color_choice)
+ {
+ case 'g':
+ {
+ *pixel++ = green;
+ } break;
+ case 'r':
+ {
+ *pixel++ = red;
+ } break;
+ case 'b':
+ {
+ *pixel++ = blue;
+ } break;
+ case 'y':
+ {
+ *pixel++ = red | green;
+ } break;
+ case 'm':
+ {
+ *pixel++ = red | blue;
+ } break;
+ case 'c':
+ {
+ *pixel++ = blue | green;
+ } break;
+ default:
+ {
+ *pixel++ = red | green | blue;
+ } break;
+ }
+ }
+ row += global_back_buffer.pitch;
+ }
+}
+
+
SDLWindowDimension
sdl_get_window_dimension(SDL_Window *window)
{
@@ -335,7 +433,7 @@ int main(void)
sdl_open_game_controllers();
SDL_Window *window = SDL_CreateWindow(
- "Tunnel Flyer",
+ "Tunnel Runner",
SDL_WINDOWPOS_UNDEFINED,
SDL_WINDOWPOS_UNDEFINED,
SCREEN_WIDTH,
@@ -351,27 +449,35 @@ int main(void)
SDLWindowDimension dimension = sdl_get_window_dimension(window);
sdl_resize_texture(&global_back_buffer, renderer, dimension.width, dimension.height);
-
uint32 texture[TEX_HEIGHT][TEX_WIDTH];
- // Make XOR texture
for (int y = 0; y < TEX_HEIGHT; ++y)
{
for (int x = 0; x < TEX_WIDTH; ++x)
{
+ // XOR texture:
texture[y][x] = (x * 256 / TEX_WIDTH) ^ (y * 256 / TEX_HEIGHT);
- //texture[y][x]= (x * x * y * y);
+ // Mosaic texture:
+ //texture[y][x] = (x * x * y * y);
}
}
-
bool running = true;
int rotation_offset = 0;
int translation_offset = 0;
char color_choice = '\0';
+ uint64_t lag = 0;
+ uint64_t previous_ms = get_current_time_ms();
+
while (running)
{
+ uint64_t current_ms = get_current_time_ms();
+ uint64_t elapsed_ms = current_ms - previous_ms;
+ previous_ms = current_ms;
+ lag += elapsed_ms;
+ //printf("Lag: %d\n", lag);
+
SDL_Event event;
while (SDL_PollEvent(&event))
@@ -498,58 +604,19 @@ int main(void)
//printf("dimension.height / 2: %d\t damp_y: %d\t raw_y: %d\n", dimension.height / 2, dampened_y, stick_righty);
}
}
+ printf("%d, %d\n", translation_offset, rotation_offset);
- // Transform texture and draw to buffer
- uint8 *row = (uint8 *)global_back_buffer.memory;
- for (int y = 0; y < global_back_buffer.height; ++y)
+ while (lag >= MS_PER_UPDATE)
{
- uint32 *pixel = (uint32 *)row;
- for (int x = 0; x < global_back_buffer.width; ++x)
- {
- int color = texture[(unsigned int)(transform.distance_table[y + transform.look_shift_y][x + transform.look_shift_x] + translation_offset) % TEX_WIDTH]
- [(unsigned int)(transform.angle_table[y + transform.look_shift_y][x + transform.look_shift_x] + rotation_offset) % TEX_HEIGHT];
-
- uint32 red = color << 16;
- uint32 green = color << 8;
- uint32 blue = color;
-
- // TODO(amin): Make a color choice enum
- switch(color_choice)
- {
- case 'g':
- {
- *pixel++ = green;
- } break;
- case 'r':
- {
- *pixel++ = red;
- } break;
- case 'b':
- {
- *pixel++ = blue;
- } break;
- case 'y':
- {
- *pixel++ = red | green;
- } break;
- case 'm':
- {
- *pixel++ = red | blue;
- } break;
- case 'c':
- {
- *pixel++ = blue | green;
- } break;
- default:
- {
- *pixel++ = red | green | blue;
- } break;
- }
- }
- row += global_back_buffer.pitch;
+ render_tunnel(global_back_buffer, texture, rotation_offset, translation_offset, color_choice);
+ //render_texture(global_back_buffer, texture, rotation_offset, translation_offset, color_choice);
+ lag -= MS_PER_UPDATE;
}
- //render_mosaic(global_back_buffer, rotation_offset, translation_offset, color_choice);
sdl_update_window(window, renderer, global_back_buffer);
+ if (elapsed_ms <= MS_PER_FRAME)
+ {
+ usleep((MS_PER_FRAME - elapsed_ms) * SECOND);
+ }
}
}
else
