void DriftingGratingStimulus::drawFrame(shared_ptr<StimulusDisplay> display) {
glPushMatrix();
glTranslatef(xoffset->getValue().getFloat(), yoffset->getValue().getFloat(), 0);
glRotatef(rotation->getValue().getFloat(),0,0,1);
GLfloat scale_size = MAX(width->getValue().getFloat(), height->getValue().getFloat());
glScalef(scale_size, scale_size, 1.0); // scale it up
// ----------------------------------------
// GRATING
// ----------------------------------------
glDisable(GL_TEXTURE_2D);
glActiveTextureARB(GL_TEXTURE0_ARB); // Associate with texture 0
glEnable(GL_TEXTURE_1D);
// select our current texture
glBindTexture( GL_TEXTURE_1D, grating_textures[display->getCurrentContextIndex()] );
// select modulate to mix texture with color for shading
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE );
// when texture area is small, bilinear filter the closest mipmap
glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST );
// when texture area is large, bilinear filter the first mipmap
glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
// if wrap is true, the texture wraps over at the edges (repeat)
// ... false, the texture ends at the edges (clamp)
glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT );
glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_REPEAT );
glEnable(GL_TEXTURE_1D);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glColor4f(1,1,1,1);
// ----------------------------------------
// MASK
// ----------------------------------------
glActiveTextureARB(GL_TEXTURE1_ARB); // associate with TEXTURE1_ARB
glEnable(GL_TEXTURE_2D);
// select our current texture
glBindTexture( GL_TEXTURE_2D, mask_textures[display->getCurrentContextIndex()] );
// select modulate to mix texture with color for shading
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE);
glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_PREVIOUS);
glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);
glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE);
glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE);
glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA_ARB, GL_SRC_ALPHA);
// ----------------------------------------
// DRAW THE QUAD
// ----------------------------------------
glBegin(GL_QUADS);
MWTime elapsed_time = getElapsedTime();
// here's the description of this equation
// starting_phase is in degrees -> degrees*pi/180 = radians
//
// speed is in degrees/second
// spatial_frequency is in cycles/degree
// elapsed_time is time since the start the 'play' in us
// us/100000 = seconds
//
// degrees cycles 1 second pi radians
// ------- * ------ * ---------- * ----------- * us = radians of phase
// s degree 1000000 us 180 degrees
//
// multiply by -1 so it the grating goes in the correct direction
double elapsed_seconds = (double)elapsed_time / (double)1000000;
const double phase = -1*(starting_phase->getValue().getFloat()*(M_PI/180.) + speed->getValue().getFloat()*spatial_frequency->getValue().getFloat()*(2.*M_PI)*elapsed_seconds);
const double direction_in_radians = direction_in_degrees->getValue().getFloat()*(M_PI/180.);
const double aspect = width->getValue().getFloat()/height->getValue().getFloat();
//mprintf("drifting grating draw (%lld - %lld = %lld, %g, %g, %g, %g)", now, start_time, elapsed_time, elapsed_seconds, phase, direction_in_radians, aspect);
const float f = cos(direction_in_radians);
const float g = sin(direction_in_radians);
const float d = ((f+g)-1)/2;
const float texture_bl = 0-d;
const float texture_br = texture_bl+f;
const float texture_tr = 1+d;
const float texture_tl = texture_bl+g;
const float mask_s_ratio = 1-MIN(1,aspect);
const float mask_t_ratio = 1-MIN(1,1/aspect);
const float phase_proportion = phase/(2*M_PI);
const float cycle_proportion = spatial_frequency->getValue().getFloat()*width->getValue().getFloat();
glNormal3f(0.0, 0.0, 1.0);
glMultiTexCoord1fARB(GL_TEXTURE0_ARB, (cycle_proportion*texture_bl)+phase_proportion);
glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0-mask_s_ratio, 0-mask_t_ratio);
glVertex3f(-0.5,-0.5,0);
glMultiTexCoord1fARB(GL_TEXTURE0_ARB, (cycle_proportion*texture_br)+phase_proportion);
glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 1+mask_s_ratio, 0-mask_t_ratio);
glVertex3f(0.5,-0.5,0);
glMultiTexCoord1fARB(GL_TEXTURE0_ARB, (cycle_proportion*texture_tr)+phase_proportion);
glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 1+mask_s_ratio, 1+mask_t_ratio);
glVertex3f(0.5,0.5,0);
glMultiTexCoord1fARB(GL_TEXTURE0_ARB, (cycle_proportion*texture_tl)+phase_proportion);
glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0-mask_s_ratio, 1+mask_t_ratio);
glVertex3f(-0.5,0.5,0);
glEnd(); // GL_QUADS
last_phase = phase*(180/M_PI);
// ----------------------------------------
// CLEAN-UP
// ----------------------------------------
// Unbind grating texture
glActiveTextureARB(GL_TEXTURE0_ARB);
glBindTexture( GL_TEXTURE_1D, 0 );
glDisable(GL_TEXTURE_1D);
// Unbind mask texture
glActiveTextureARB(GL_TEXTURE1_ARB);
glBindTexture( GL_TEXTURE_2D, 0 );
glDisable(GL_TEXTURE_2D);
glActiveTextureARB(0);
//
// If alpha_multiplier is less than 1, draw another polygon on top to reduce contrast
//
float tB = alpha_multiplier->getValue().getFloat();
if ((tB < 1.0f) && (tB >= 0.0f)) {
glBegin(GL_QUADS);
glColor4f(0.5,0.5,0.5,1-tB); // MH 100730 I believe all grating types have mean 0.5 hardcoded now, fade to 0.5
glVertex3f(-0.5,-0.5,0);
glVertex3f(0.5,-0.5,0);
glVertex3f(0.5,0.5,0);
glVertex3f(-0.5,0.5,0);
glEnd(); // GL_QUADS
}
glPopMatrix();
}
void __stdcall glMultiTexCoord1f(GLenum target, GLfloat s)
{
if (!ARB_multitexture) return;
glMultiTexCoord1fARB(target, s);
}
