Fog

Hardware Fog API for the PowerVR. More...

Functions
void	pvr_fog_table_color (float a, float r, float g, float b)
	Set the table fog color.
void	pvr_fog_vertex_color (float a, float r, float g, float b)
	Set the vertex fog color.
void	pvr_fog_far_depth (float d)
	Set the fog far depth.
void	pvr_fog_table_exp2 (float density)
	Initialize the fog table using an exp2 algorithm (like GL_EXP2).
void	pvr_fog_table_exp (float density)
	Initialize the fog table using an exp algorithm (like GL_EXP).
void	pvr_fog_table_linear (float start, float end)
	Initialize the fog table using a linear algorithm (like GL_LINEAR).
void	pvr_fog_table_custom (float tbl1[])
	Set a custom fog table from float values.

Detailed Description

Hardware Fog API for the PowerVR.

Note

Thanks to Paul Boese for figuring this stuff out

Function Documentation

pvr_fog_far_depth()

void pvr_fog_far_depth

(

float

d

)

Set the fog far depth.

This function sets the PVR_FOG_DENSITY register appropriately for the specified value.

Parameters

d	The depth to set

pvr_fog_table_color()

void pvr_fog_table_color	(	float	a,
		float	r,
		float	g,
		float	b
	)

Set the table fog color.

This function sets the color of fog for table fog. 0-1 range for all colors.

Parameters

a	Alpha value of the fog
r	Red value of the fog
g	Green value of the fog
b	Blue value of the fog

pvr_fog_table_custom()

void pvr_fog_table_custom

(

float

tbl1[]

)

Set a custom fog table from float values.

This function allows you to specify whatever values you need to for your fog parameters. All values should be clamped between 0 and 1, and its your responsibility to set up the PVR_FOG_DENSITY register by calling pvr_fog_far_depth() with an appropriate value. The table passed in should have 129 entries, where the 0th entry is farthest from the eye and the last entry is nearest. Higher values = heavier fog.

Parameters

tbl1	The table of fog values to set

pvr_fog_table_exp()

void pvr_fog_table_exp

(

float

density

)

Initialize the fog table using an exp algorithm (like GL_EXP).

This function will automatically set the PVR_FOG_DENSITY register to 259.999999 as a part of its processing, then set up the fog table.

Parameters

density

Fog density value

pvr_fog_table_exp2()

void pvr_fog_table_exp2

(

float

density

)

Initialize the fog table using an exp2 algorithm (like GL_EXP2).

This function will automatically set the PVR_FOG_DENSITY register to 259.999999 as a part of its processing, then set up the fog table.

Parameters

density

Fog density value

pvr_fog_table_linear()

void pvr_fog_table_linear	(	float	start,
		float	end
	)

Initialize the fog table using a linear algorithm (like GL_LINEAR).

This function will set the PVR_FOG_DENSITY register to the as appropriate for the end value, and initialize the fog table for perspectively correct linear fog.

Parameters

start	Fog start point
end	Fog end point

pvr_fog_vertex_color()

void pvr_fog_vertex_color	(	float	a,
		float	r,
		float	g,
		float	b
	)

Set the vertex fog color.

This function sets the fog color for vertex fog. 0-1 range for all colors. This function is currently not implemented, as vertex fog is not supported by KOS. Calling this function will cause an assertion failure.

Parameters

a	Alpha value of the fog
r	Red value of the fog
g	Green value of the fog
b	Blue value of the fog