Difference between revisions of "Modules/game pawn/Usage"
From MSX Game Library
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'''Example:''' | '''Example:''' | ||
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A two color sprite (2 layer): <syntaxhighlight lang="C"> | A two color sprite (2 layer): <syntaxhighlight lang="C"> | ||
const Game_Sprite g_SpriteLayers[] = | const Game_Sprite g_SpriteLayers[] = | ||
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Once the sprite and animation data have been defined, the pawn must be initialized. | Once the sprite and animation data have been defined, the pawn must be initialized. | ||
| − | <syntaxhighlight lang="c">GamePawn_Initialize(&g_PlayerPawn, g_SpriteLayers, numberof(g_SpriteLayers), 0, g_AnimActions); // Initialize pawn structure | + | '''Examples:''' <syntaxhighlight lang="c">GamePawn_Initialize(&g_PlayerPawn, g_SpriteLayers, numberof(g_SpriteLayers), 0, g_AnimActions); // Initialize pawn structure |
GamePawn_SetPosition(&g_PlayerPawn, 16, 16); // Set pawn position</syntaxhighlight> | GamePawn_SetPosition(&g_PlayerPawn, 16, 16); // Set pawn position</syntaxhighlight> | ||
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=== Initialize pawn === | === Initialize pawn === | ||
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/* ... */ | /* ... */ | ||
| − | GamePawn_InitializePhysics(&g_PlayerPawn, PhysicsEvent, PhysicsCollision, 16, 16); // | + | GamePawn_InitializePhysics(&g_PlayerPawn, PhysicsEvent, PhysicsCollision, 16, 16); // Initialize pawn physics</syntaxhighlight> |
Latest revision as of 00:20, 19 April 2024
Contents
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 offset of the layer relative to the Pawn position, 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_FramesPunch[] =
{
{ 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_FramesPunch, numberof(g_FramesFall), FALSE, FALSE }, // Play once, can't be interrupted
};
Initialize pawn
All pawn management is carried out via a Game_Pawn structure (each pawn must have its own structure). Once the sprite and animation data have been defined, the pawn must be initialized.
Examples: GamePawn_Initialize(&g_PlayerPawn, g_SpriteLayers, numberof(g_SpriteLayers), 0, g_AnimActions); // Initialize pawn structure GamePawn_SetPosition(&g_PlayerPawn, 16, 16); // Set pawn position
Initialize pawn
If you want to use the physics and collision functionalities, you must set the GAMEPAWN_USE_PHYSICS option in your library configuration file (msxgl_config.h). Next, you need to define two callback functions:
- one that determines whether a given block of background is a blocker or not,
- and the other which receives collision-related events (touching the screen edge, falling, etc.).
// Physics callback
void PhysicsEvent(u8 event, u8 tile)
{
switch(event)
{
case PAWN_PHYSICS_BORDER_DOWN:
case PAWN_PHYSICS_BORDER_RIGHT:
case PAWN_PHYSICS_COL_DOWN: // Handle downward collisions
case PAWN_PHYSICS_COL_UP: // Handle upward collisions
case PAWN_PHYSICS_FALL: // Handle falling
break;
};
}
// Collision callback
bool PhysicsCollision(u8 tile)
{
return (tile & 0x80);
}
/* ... */
GamePawn_InitializePhysics(&g_PlayerPawn, PhysicsEvent, PhysicsCollision, 16, 16); // Initialize pawn physics