Sprites

C library to draw sprites.

Usage

Project Level

Your application's build pipeline will need to be configured to compile each C file in the src directory and recompile every C file should any H files change. Then, include each H file in the same directory to make its corresponding function available.

Assumptions

• The compilation environment supports C99.
• The sprite being sampled from:
  • Has its origin in the top left corner.
  • Is row-major.
  • Is planar (not interleaved).
  • Has a red plane.
  • Has a green plane.
  • Has a blue plane.
  • Has an opacity plane (where required).
  • Uses 32-bit floats for all planes.
  • Describes absolute transparency as an opacity of 0.
  • Describes absolute opacity as an opacity of 1.
  • Does not pre-multiply any plane by the opacity plane.
• The viewport being rendered to:
  • Has its origin in the top left corner.
  • Is row-major.
  • Is planar (not interleaved).
  • Has a red plane.
  • Has a green plane.
  • Has a blue plane.
  • Has an opacity plane.
  • Uses 32-bit floats for all planes.
  • Describes absolute transparency as an opacity of 0.
  • Describes absolute opacity as an opacity of 1.
  • Does not pre-multiply any plane by the opacity plane.
• No float arguments:
  • Are NaN.
  • Are infinity.
  • Are negative infinity.
  • Cannot be cast to int without undefined behavior (for example, very large values).

Blend Modes

Blend Mode	Color	Opacity
Opaque	Overwritten.	Overwritten with 1.
Cutout	Overwritten or unchanged.	Overwritten with 1 or unchanged.
Additive	Summed ("linear dodge").	Unchanged.
Blended	Mixed using opacity.	Mixed with opacity.

Functions

Name	Type	Blend Mode
opaque_sprite	Draw	Opaque
cutout_sprite	Draw	Cutout
additive_sprite	Draw	Additive
blended_sprite	Draw	Blended

Tests

Execute make to run the test suite.

Dependencies

• Make.
• MinGW-GCC for Windows, Clang for all other platforms.
• Bash.