Let's start

posted in BKP Game journal
Published March 01, 2018
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Hi everybody,

After my first game and story, it is time to start the new one with more experience this time.

The primary goal is to avoid the same mistakes, so I will start to talk about it now. It is not the very beginning as I already have 11000 lines of codes. From Soul of Mask experiences, I learn that I should talk about my game as soon as possible. So I will introduce the new game to my two favourite forums GDN and another one in French:

  • Game name: Not sure about it yet and it is not so important now.
  • Game genre: Platform, Adventure. (kind of limbo and Ninja Gaiden mixt)
  • Programming: C core engine, C or C++ game (not decided yet)
  • Graphics: 2D/3D.
  • Graphics lib: OpenGL > 3.5
  • Audio: Not sure yet (probably OpenAl)
  • Platforms: for the moment Windows 10 and Linux (other may come later or not)
  • Relative to the game ( story, artwork, ....): As I said it didn't start already, but story big picture is finished.

So what am I doing now?

I am finishing the first part that will make me decide if I continue the project or not. It is essentially technical like object collision, sprite animation, learning more about platform game technic...

What did I do?

Well, I decided to not use SDL2 as I want to port my game in some platform that does not support SDL. So I choose OpenGL. Plus I plan to use some 3D features in the game. So I mocked SDL2 behaviour and write it very specifically for my game.

bkp.png.32e2768539a9c2e6716f260c39af9e62.png

Here is a screenshot that shows objects rotating. I used a sprite sheet from Soul of Mask, we can also see a red box and a rectangle coming from a function call drawRectangle (more details soon)

here we can see the code I will need to write for an animation:


   bkp_graphics_2dReady(BKP_TRUE);

    BKP_Rec dest,src;
    BKP_Rotate r;
    src.w = 64; 
    src.h = 64; 
    src.x = 2;
    src.y = 2;

    dest.w = 92; 
    dest.h = 92; 
    dest.x = 500;
    dest.y = 200;

    static float iii = 0;
    static double tm = 0;
    static double ta = 0;
    static int alpha = 255 ;
    static int dal = 2;
    tm = glfwGetTime();
        
    //animation timers
    if(tm - ta > 64.0f / 1000.0f)
    {   
        ta = tm; 
        iii += .125;

        if(alpha <=0 || alpha >=255)
            dal = -dal;
        alpha += dal;
    }

    r.center.z = 0;
    r.angle = -iii;
    r.center.x = dest.x + dest.w / 2;
    r.center.y = dest.y + dest.h / 2;
        
    bkp_graphics_drawSurface(G[0] ,&dest,&src,&r,BKP_GRAPHICS_FLIPNONE, &alpha);
        
    dest.w = 368;
    dest.h = 138;
    dest.x -= 35; 
    dest.y -= 20; 
    bkp_graphics_2dsetColori(255,255,255,255);
    bkp_graphics_drawRectangle(&dest, BKP_FALSE);

    dest.w = 168;
    dest.x = 250;
    r.angle = iii;
    bkp_graphics_drawSurface(G[2] ,&dest,&src,&r,BKP_GRAPHICS_FLIPH, NULL);

    r.angle = -iii /4; 
    bkp_graphics_drawSurface(G[0] ,&dest,&src,&r,BKP_GRAPHICS_FLIPV, NULL);

    dest.x = 620;
    bkp_graphics_2dsetColori(255,0,0,255 / 2); 
    bkp_graphics_drawRectangle(&dest, BKP_TRUE);
        
    bkp_graphics_2dFlush();

Looks a little bit like SDL. In this example we can see all the job done so far, Scaling, Positioning, FLIP (vertical, horizontal), Rotate around a point and transparency. Those are all I used with SDL2 so far for Soul of Mask. The first objective is checked. Here is a video that illustrates it:

 

bkp-2018-03-01_15.32.12

   I don't go into the deep details about how I did things, but if people request it in the comments I will, I mean I would like to share it as I think some people who use OpenGL better than I do may give me some precious pieces of advice and improve the way I did it, in the meantime more beginner than I am will have a hint to start. 

Time for a little of performance:

The graphics engine is able to draw on those 3 differents devices (here GPU integrated in CPU)

  - draw a frame in 0.016 ms for 1700 animated sprites on a Intel(R) Core(TM) i5-4210U CPU 1366x768

  - draw a frame in 0.016 ms for 1000 animated sprites on a Broadwell Intel Core M-5Y70 HD 4k

  - draw a frame in 0.016 ms for 7000 animated sprites on a Intel(R) Core(TM) i7-7700 CPU 1920x1080

I didn't test it with a Nvidia or Radeon graphics card yet, for the moment it is irrelevant but it will come later.

 

Conclusion on using custom vs SDL2

pro: Faster. I know everything behind it.

con: Fewer features, less flexible, unoptimized and probably full of bugs I didn't notice yet.

 

I also added a log system I didn't have it for my previous game so at any crash I add to try to reproduce it very hard now it is better just have to read log file on crashes.

here is the output of this video:


DEBUG set
Moving to directory `../`
[ INFO  ][ 2018-03-01 15:27:06] -> Starting Graphics Engine ...
[ INFO  ][ 2018-03-01 15:27:06] -> Starting GLFW 3.2.1 X11 GLX EGL clock_gettime /dev/js Xf86vm shared
[ INFO  ][ 2018-03-01 15:27:06] -> Monitor info:
[ INFO  ][ 2018-03-01 15:27:06] -> #1 1920x1080
[ INFO  ][ 2018-03-01 15:27:06] -> #0 1366x768
[ INFO  ][ 2018-03-01 15:27:06] -> --------------------------

[ INFO  ][ 2018-03-01 15:27:06] -> GL Context Params : 
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS : 192
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_CUBE_MAP_TEXTURE_SIZE : 16384
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_DRAW_BUFFERS : 8
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_FRAGMENT_UNIFORM_COMPONENTS : 16384
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_TEXTURE_IMAGE_UNITS : 32
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_TEXTURE_SIZE : 16384
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_VARYING_FLOATS : 128
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_VERTEX_ATTRIBS : 16
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS : 32
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_VERTEX_UNIFORM_COMPONENTS : 16384
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_MULTISAMPLE_COVERAGE_MODES_NV : 0
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_SAMPLES : 8
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_MULTISAMPLE_COVERAGE_MODES_NV : 32768 : 32768
[ INFO  ][ 2018-03-01 15:27:06] -> GL_MAX_SAMPLES : 0
[ INFO  ][ 2018-03-01 15:27:06] -> --------------------------

[ INFO  ][ 2018-03-01 15:27:06] -> Opening window with GLFW3 [OK]
[ INFO  ][ 2018-03-01 15:27:06] -> Renderer : Mesa DRI Intel(R) Haswell Mobile 
[ INFO  ][ 2018-03-01 15:27:06] -> OpenGL version : 4.5 (Core Profile) Mesa 17.2.4
[ INFO  ][ 2018-03-01 15:27:06] -> 4.5
[ INFO  ][ 2018-03-01 15:27:06] -> program 3 GL_VALIDATE_STATUS = 1:
[ INFO  ][ 2018-03-01 15:27:06] -> ------------- shader programme 3 info ---------------
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_LINK_STATUS = 1:
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ATTACHED_SHADERS = 2:
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ACTIVE_ATTRIBUTES = 1:
[ INFO  ][ 2018-03-01 15:27:06] -> 		0) type:vec3 name: vp location: 0
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ACTIVE_UNIFORMS = 2:
[ INFO  ][ 2018-03-01 15:27:06] -> 		0) type:mat4 name: matrix location: 0
[ INFO  ][ 2018-03-01 15:27:06] -> 		1) type:vec4 name: color location: 1
[ INFO  ][ 2018-03-01 15:27:06] -> ------------- end info ---------------
[ INFO  ][ 2018-03-01 15:27:06] -> program 6 GL_VALIDATE_STATUS = 1:
[ INFO  ][ 2018-03-01 15:27:06] -> ------------- shader programme 6 info ---------------
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_LINK_STATUS = 1:
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ATTACHED_SHADERS = 2:
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ACTIVE_ATTRIBUTES = 2:
[ INFO  ][ 2018-03-01 15:27:06] -> 		0) type:vec3 name: vertex_position location: 0
[ INFO  ][ 2018-03-01 15:27:06] -> 		1) type:vec2 name: vt_loc location: 1
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ACTIVE_UNIFORMS = 3:
[ INFO  ][ 2018-03-01 15:27:06] -> 		0) type:mat4 name: matrix location: 0
[ INFO  ][ 2018-03-01 15:27:06] -> 		1) type:vec4 name: vt_ location: 1
[ INFO  ][ 2018-03-01 15:27:06] -> 		2) type:sampler2D name: basic_texture location: 2
[ INFO  ][ 2018-03-01 15:27:06] -> ------------- end info ---------------
[ INFO  ][ 2018-03-01 15:27:06] -> program 9 GL_VALIDATE_STATUS = 1:
[ INFO  ][ 2018-03-01 15:27:06] -> ------------- shader programme 9 info ---------------
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_LINK_STATUS = 1:
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ATTACHED_SHADERS = 2:
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ACTIVE_ATTRIBUTES = 2:
[ INFO  ][ 2018-03-01 15:27:06] -> 		0) type:vec3 name: vertex_position location: 0
[ INFO  ][ 2018-03-01 15:27:06] -> 		1) type:vec2 name: vt_loc location: 1
[ INFO  ][ 2018-03-01 15:27:06] -> 		GL_ACTIVE_UNIFORMS = 4:
[ INFO  ][ 2018-03-01 15:27:06] -> 		0) type:mat4 name: matrix location: 0
[ INFO  ][ 2018-03-01 15:27:06] -> 		1) type:vec4 name: vt_ location: 1
[ INFO  ][ 2018-03-01 15:27:06] -> 		2) type:sampler2D name: basic_texture location: 2
[ INFO  ][ 2018-03-01 15:27:06] -> 		3) type:float name: alpha_factor location: 3
[ INFO  ][ 2018-03-01 15:27:06] -> ------------- end info ---------------
[ INFO  ][ 2018-03-01 15:27:06] -> 2D Graphics Engine start [OK]
[ INFO  ][ 2018-03-01 15:27:06] -> Graphics Engine started
[ INFO  ][ 2018-03-01 15:27:17] -> 

[ INFO  ][ 2018-03-01 15:27:17] -> deleting shader programe 3
[ INFO  ][ 2018-03-01 15:27:17] -> deleting shader programe 6
[ INFO  ][ 2018-03-01 15:27:17] -> deleting shader programe 9
[ INFO  ][ 2018-03-01 15:27:17] -> 2D Graphics  Engine closed [OK]
[ INFO  ][ 2018-03-01 15:27:17] -> Window closed [OK]
[ INFO  ][ 2018-03-01 15:27:17] -> Graphics Engine stopped [OK]
[ INFO  ][ 2018-03-01 15:27:17] -> Logger closed [OK]
[ INFO  ][ 2018-03-01 15:27:17] -> Game Engine stopped [OK]

What's next?

   I am learning about the type of game I am doing, I should have some basic movement of main character and platform collisions soon. I promise myself I will not do everything alone again so this blog will be also used to seduce whoever want to jump into this adventure. But by experience I know I may finish alone again (who knows).

Thanks for reading, I will post more as soon as I have something new to show.

Have a nice day.

Next Entry Min collisions
2 likes 5 comments

Comments

Rutin

Nice job!

March 02, 2018 03:32 PM
lilington

Thanks, something will be finished this week-end (I hope)

March 03, 2018 02:59 AM
Rutin
On 3/2/2018 at 7:59 PM, lilington said:

Thanks, something will be finished this week-end (I hope)

How's the project coming along?

March 14, 2018 03:05 AM
lilington

Hello,

Minimal input module (keyboard only by now) is finish.

gravity is finished, objet can jump and fall but no collision, so just fall down out of screen.

At this moment, I am trying to solve a deformation after rotation, looks like projection matrix is wrong somewhere.  I need to solve this before i continue to collisions.

March 15, 2018 12:13 AM
Rutin

Nice job! :) 

March 15, 2018 08:28 PM
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