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Initial implementation of the 2D map interpolation

This commit is contained in:
Josh Stewart 2013-02-05 20:41:41 +11:00
parent 24e79171af
commit 9cd43ebd79
2 changed files with 62 additions and 10 deletions
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62
table.h
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@ -7,9 +7,10 @@ struct table {
const static int xSize = 8;
const static int ySize = 8;
int values[xSize][ySize];
int axisX[xSize];
int axisY[ySize];
int values[ySize][xSize];
//int axisX[xSize];
int axisX[];
int axisY[];
//static boolean useInterp = false; //Whether or not interpolation should be used (Assuming we have enough CPU for it)
};
@ -28,11 +29,62 @@ Eg: 2x2 table
*/
//This function pulls a value from a table given a target for X and Y coordinates.
//It performs a 2D linear interpolation as descibred in: http://www.megamanual.com/v22manual/ve_tuner.pdf
int getTableValue(struct table fromTable, int Y, int X)
{
for (int x = 0; x < fromTable.xSize; x++)
//Loop through the X axis bins for the min/max pair
//Note: For the X axis specifically, rather than looping from tableAxisX[0] up to tableAxisX[max], we start at tableAxisX[Max] and go down.
// This is because the important tables (fuel and injection) will have the highest RPM at the top of the X axis, so starting there will mean the best case occurs when the RPM is highest (And hence the CPU is needed most)
int xMin = fromTable.axisX[0];
int xMax = fromTable.axisX[fromTable.xSize];
for (int x = fromTable.xSize; x > 0; x--)
{
if ( (X < fromTable.axisX[x]) && (X > fromTable.axisX[x-1]) )
{
xMax = fromTable.axisX[x];
xMin = fromTable.axisX[x-1];
break;
}
}
//Loop through the Y axis bins for the min/max pair
int yMin = fromTable.axisY[0];
int yMax = fromTable.axisY[fromTable.ySize];
for (int y = fromTable.ySize; y > 0; y--)
{
if ( (Y < fromTable.axisY[y]) && (Y > fromTable.axisY[y-1]) )
{
yMax = fromTable.axisY[y];
yMin = fromTable.axisY[y-1];
break;
}
}
/*
At this point we have the 4 corners of the map where the interpolated value will fall in
Eg: (yMin,xMin) (yMin,xMax)
(yMax,xMin) (yMax,xMax)
In the following calculation the table values are referred to by the following variables:
A B
C D
*/
int A = fromTable.values[yMin][xMin];
int B = fromTable.values[yMin][xMax];
int C = fromTable.values[yMax][xMin];
int D = fromTable.values[yMax][xMax];
//Create some normalised position values
float p = ((float)(X - xMin)) / (xMax - xMin);
float q = ((float)(Y - yMax)) / (yMax - yMin);
float m = (1.0-p)(1.0-q);
return 1;
}

10
testing.h
View File

@ -13,8 +13,7 @@ _____________________________________________
| 50|
| 38|
| 25|
| 13|
| 1| 15 | 20 |
| 13| 15 | 20 |
| | 500|1500|2000|2500|3000|4000|5000|6000| RPM
This is a fairly standard 8x8 VE vs RPM 2D map
@ -25,7 +24,8 @@ void dummyFuelTable()
{
table myFuelTable;
//myFuelTable.values
//myFuelTable.axisY = {100,88,75,63,50,38,25,13,1};
//myFuelTable.axisX = {500,1500,2500,3000,4000,5000,6000};
int tempXAxis[8] = {100,88,75,63,50,38,25,13};
*myFuelTable.axisY = *tempXAxis;
int tempYAxis[8] = {500,1500,2500,3000,4000,5000,6000};
*myFuelTable.axisY = *tempYAxis;
}