Modules/game pawn

The game_pawn module handle character animation, rendering, collision and physics.

This module offer several structures the user can use to configure a pawn (a player, an enemy or any moving object) for rendering (multi-layers and flip/flap) and movement.

Dependencies

• vdp
• memory

Settings

• GAMEPAWN_USE_PHYSICS: Include collision and physics handling functions. Can be 0 or 1.
• GAMEPAWN_COL_DOWN: Points used for down direction collision. Can be any combinaison of:
  • GAMEPAWN_COL_0
  • GAMEPAWN_COL_25
  • GAMEPAWN_COL_50
  • GAMEPAWN_COL_75
  • GAMEPAWN_COL_100
• GAMEPAWN_COL_UP: Points used for up direction collision
• GAMEPAWN_COL_RIGHT: Points used for right direction collision
• GAMEPAWN_COL_LEFT: Points used for left direction collision
• GAMEPAWN_BORDER_EVENT: (GAMEPAWN_BORDER_DOWN|GAMEPAWN_BORDER_RIGHT)
• GAMEPAWN_BORDER_BLOCK: (GAMEPAWN_BORDER_UP|GAMEPAWN_BORDER_LEFT)
• GAMEPAWN_BORDER_MIN_Y: 0
• GAMEPAWN_BORDER_MAX_Y: 191

Usage

Define pawn's sprites

The visual of a pawn is defined by one or more sprite layers. The Game_Sprite structure allows to define the parameters of each layer : The X/Y position of the layer relative to the Pawn, the pattern number offset from the pattern number defined in the animation, the sprite color and a special flag for display.

Example:

A two color sprite (2 layer): ‎

const Game_Sprite g_SpriteLayers[] =
{
	{ 0, 0, 0,  COLOR_WHITE, 0 }, // Sprite position offset: 0,0. Pattern offset: 0. Color: White. No special flag
	{ 0, -8, 4,  COLOR_GRAY, 0 }, // Sprite position offset: 0,-8. Pattern offset: 4. Color: Gray. No special flag
};
‎

Define pawn's animations

Each animation is defined by a list of Game_Frame structures that determine : The pattern number of the animation frame, the duration of the frame in number of display cycles, and a function to call when the character reach a given frame of the animation. Create a structure for each animation. You have to provide a complete list of all action that the pawn can do.

Example:

Push animation with function to trigger ‎

const Game_Frame g_FramePunch[] =
{
	{ 0,	4,	null }, // Display pattern 0 for 4 render cycles
	{ 8,	4,	null },
	{ 8,	1,	DoPunch }, // call function DoPunch() when Pawn is displaying this frame
	{ 16,	4,	null },
	{ 24,	4,	null },
};
‎

Define pawn's actions

An action is defined in the Game_Action structure and include a animation plus some parameters like the looping of the animation or a flag to determine if the action can be interrupted.

Examples:

‎

const Game_Action g_AnimActions[] =
{ //  Frames        Number                  Loop? Interrupt?
	{ g_FramesIdle, numberof(g_FramesIdle), true, true },
	{ g_FramesMove, numberof(g_FramesMove), true, true },
	{ g_FramesJump, numberof(g_FramesJump), true, true },
	{ g_FramesFall, numberof(g_FramesFall), true, true },
};
‎

Annexe

• See also : Sample program s_game