I would also use quads. If you need screen-aligned billboards, you
can use the rows of the model-view matrix (assuming scale is 1) as the
basis for drawing the quad. For example:
//screen-aligned axes
vec3 axis1 = vec3( gl_ModelViewMatrix[0][0],
gl_ModelViewMatrix[1][0],
gl_ModelViewMatrix[2][0]);
vec3 axis2 = vec3( gl_ModelViewMatrix[0][1],
gl_ModelViewMatrix[1][1],
gl_ModelViewMatrix[2][1]);
wes
On Fri, May 30, 2008 at 8:39 AM, Kent Miller <email@hidden> wrote:
> Point sprites do this.
>
> I would just look at using quads. I don't think there is much advantage to
> point sprites unless you are doing something like a particle system with
> thousands of points in which case point sprites can take your vertex data
> rate down. GL Points have their own special set of quirks.
>
> Kent
>
> On May 30, 2008, at 8:30 AM, Mike wrote:
>
>> I am mapping texture to GL_POINT.
>> My point size varies but lets say it's 5x5 pixels. Currently the whole
>> point just samples single pixel from texture and point's texels are all that
>> same color.
>>
>> How can I (or can I) map it so that it all texels in point are sampled
>> (1:1) from texture? i.e. if texture is 100 x 100px and point is 25x25px
>> (not smoothed) the point should represent 1/4 region of texture and with 4
>> points I could represent whole texture.
>>
>> Thanks.
>>
>> -Mike
>>
>>
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